diff options
Diffstat (limited to 'Principles_Of_Heat_Transfer_by_F_Kreith')
10 files changed, 6281 insertions, 0 deletions
diff --git a/Principles_Of_Heat_Transfer_by_F_Kreith/1-Basic_Modes_of_Heat_Transfer.ipynb b/Principles_Of_Heat_Transfer_by_F_Kreith/1-Basic_Modes_of_Heat_Transfer.ipynb new file mode 100644 index 0000000..50dd4df --- /dev/null +++ b/Principles_Of_Heat_Transfer_by_F_Kreith/1-Basic_Modes_of_Heat_Transfer.ipynb @@ -0,0 +1,768 @@ +{ +"cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Chapter 1: Basic Modes of Heat Transfer" + ] + }, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 1.10: Heat_Loss_From_Pipe.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 1 Example # 1.10 ')\n", +"\n", +"//diameter of pipe in m\n", +"d = 0.5;\n", +"//Epsilon is given as\n", +"epsilon = 0.9;\n", +"//sigma(constant) in SI units is\n", +"sigma = 0.0000000567;\n", +"//Temperatures in K are given as\n", +"T1 = 500;\n", +"T2 = 300;\n", +"\n", +"//Radiation heat transfer coefficient in W/m2K\n", +"hr = ((sigma*epsilon)*(T1*T1+T2*T2))*(T1+T2);\n", +"\n", +"//Convection heat transfer coefficient in W/m2K\n", +"hc = 20;\n", +"\n", +"//total heat transfer coefficient in W/m2K\n", +"h = hc+hr;\n", +"\n", +"disp('Rate of heat loss per meter in W/m is')\n", +"//Rate of heat loss per meter in W/m\n", +"q = ((%pi*d)*h)*(T1-T2)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 1.11: Heat_Exchanger_Analysis.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 1 Example # 1.11 ')\n", +"\n", +"//Hot-gas temperature in K\n", +"Tgh = 1300;\n", +"//Heat transfer coefficient on hot side in W/m2K\n", +"h1 = 200;\n", +"//Heat transfer coefficient on cold side in W/m2K\n", +"h3 = 400;\n", +"//Coolant temperature in K\n", +"Tgc = 300;\n", +"//Max temp. in C\n", +"Tsg = 800;\n", +"//Maximum permissible unit thermal resistance per square meter of the metal wall in K/W\n", +"R2 = (Tgh-Tgc)/((Tgh-Tsg)/(1/h1))-1/h1-1/h3;\n", +"disp('Maximum permissible unit thermal resistance per square meter of the metal wall in m2.K/W is')\n", +"R2" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 1.12: Insulation_in_Gas_Furnace.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 1 Example # 1.12 ')\n", +"\n", +"// total length of metal sheet in m\n", +"L = 0.625/39.4;\n", +"// we estimate the thermal conductivity of the metal sheets to be approximately 43 W/m K\n", +"k = 43;\n", +"// therefore the resistance in K/W offered by metal sheey\n", +"R = L/k;\n", +"\n", +"//heat loss in W/m2 is given as\n", +"q = 1200;\n", +"// overall heat transfer coefficient between the gas and the door is given\n", +"// in W/m2K\n", +"U = 20;\n", +"//The temperature drop between the gas and the interior surface of the door at the specified heat flux is\n", +"deltaT1 = q/U;\n", +"//Hence, the temperature of the Inconel will be in degree C\n", +"T = 1200-deltaT1;\n", +"\n", +"//The heat transfer coefficient between the outer surface of the door and\n", +"//the surroundings at 20°C in W/m2K\n", +"h = 5;\n", +"//The temperature drop at the outer surface in degree C is\n", +"deltaT2 = q/h;\n", +"//Selecting milled alumina-silica chips as insulator (Fig 1.31 on page 48)\n", +"\n", +"// Hence, temperature difference across the insulation is\n", +"deltaT3 = T-deltaT1-deltaT2;\n", +"\n", +"//thermal conductivity for milled alumina-silica chips in W/mK is\n", +"k = 0.27;\n", +"\n", +"disp('The insulation thickness in m is')\n", +"//The insulation thickness in m\n", +"L = (k*deltaT3)/q" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 1.13: Energy_Balance_at_Roof.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 1 Example # 1.13 ')\n", +"\n", +"//Temperature of air in degree K\n", +"Tair = 300;\n", +"//Heat transfer coefficient in W/m2K\n", +"h = 10;\n", +"\n", +"disp('Part a')\n", +"//Radiation solar flux in W/m2\n", +"q = 500;\n", +"//Ambient temperature in K\n", +"Tsurr = 50;\n", +"\n", +"disp('Solving energy balance equaiton by trial and error for the roof temperature, we get temp. in degree K')\n", +"//Room temperature in degree K\n", +"Troof = 303\n", +"\n", +"disp('Part b')\n", +"\n", +"//No heat flux, energy balance equaiton is modified\n", +"disp('Room temperature in degree K')\n", +"//Room temperature in degree K\n", +"Troof = 270" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 1.14: Theoretical_example.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 1 Example # 1.14 ')\n", +"\n", +"disp('The given example is theoretical and does not involve any numerical computation')" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 1.1: Heat_Loss_Through_a_Brick_Wall.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 1 Example # 1.1 ')\n", +"\n", +"//Temperature Inside in F\n", +"Ti = 55;\n", +"//Temperature outside in F\n", +"To = 45;\n", +"//Thickness of the wall in ft\n", +"t = 1;\n", +"//Heat loss through the wall in Btu/h-ft2\n", +"q = 3.4;\n", +"\n", +"//Converting Btu/h-ft2 to W/m2\n", +"disp('Heat loss through the wall in W/m2 is')\n", +"//Heat loss through the wall in W/m2 \n", +"qdash = (q*0.2931)/0.0929\n", +"\n", +"//Heat loss for a 100ft2 surface over a 24-h period\n", +"disp('Heat loss for a 100ft2 surface over a 24-h period in Btu is')\n", +"//Heat loss for a 100ft2 surface over a 24-h period in Btu \n", +"Q = (q*100)*24\n", +"\n", +"//Q in SI units i.e. kWh\n", +"Q = (Q*0.2931)/1000;\n", +"\n", +"//At price of 10c/kWh, the total price shall be\n", +"disp('So, the total price in c are')\n", +"//Total price in c\n", +"Price = 10*Q" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 1.2: Heat_Transfer_Through_a_Window_Glass.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 1 Example # 1.2 ')\n", +"\n", +"//Thermal conductivity of window glass in W/m-K\n", +"k = 0.81;\n", +"//Height of the glass in m\n", +"h = 1;\n", +"//Width of the glass in m\n", +"w = 0.5;\n", +"//Thickness of the glass in m\n", +"t = 0.005;\n", +"//Outside temperature in C\n", +"T2 = 24;\n", +"//Inside temperature in C\n", +"T1 = 24.5;\n", +"\n", +"//Assume that steady state exists and that the temperature is uniform over the inner and outer surfaces\n", +"\n", +"//Cross sectional area in m2\n", +"A = h*w;\n", +"\n", +"disp('Thermal resistance to conduction in K/W is')\n", +"//Thermal resistance to conduction in K/W\n", +"R = t/(k*A)\n", +"\n", +"//The rate of heat loss from the interior to the exterior surface is\n", +"//obtained by dividing temperature difference from the thermal resistence\n", +"\n", +"disp('Heat loss in W from the window glass is')\n", +"//Heat loss in W\n", +"q = (T1-T2)/R" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 1.3: Natural_Convection_Between_Air_and_Roof.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 1 Example # 1.3 ')\n", +"\n", +"//Area of room in m2 is given as\n", +"A = 20*20;\n", +"//Air temperature in C\n", +"Tair = -3;\n", +"//Roof temperature in C\n", +"Troof = 27;\n", +"//Heat transfer coefficient in W/m2-K\n", +"h = 10;\n", +"\n", +"//Assume that steady state exists and the direction of heat flow is from the\n", +"//roof to the air i.e higher to lower temperature (as it should be).\n", +"\n", +"disp(' The rate of heat transfer by convection from the roof to the air in W')\n", +"//The rate of heat transfer by convection from the roof to the air in W\n", +"q = (h*A)*(Troof-Tair)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 1.4: Analysis_of_Electrically_Heated_Rod.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 1 Example # 1.4 ')\n", +"\n", +"//Diameter of rod in m\n", +"d = 0.02;\n", +"// Emissivity and temperautre of rod in K\n", +"epsilon = 0.9;\n", +"T1 = 1000;\n", +"//Temperature of walls of furnace\n", +"T2 = 800;\n", +"\n", +"//Assuming steady state has been reached.\n", +"//Since the walls of the furnace completely enclose the heating rod, all the radiant energy emitted by the surface of the rod is intercepted by the furnace walls\n", +"\n", +"//From eq. 1.17, net heat loss can be given\n", +"\n", +"disp('Net heat loss per unit length considering 1m length in W')\n", +"//Area in m2\n", +"A = (%pi*d)*1;\n", +"//Constant sigma in W/m2-K4\n", +"sigma = 0.0000000567;\n", +"//Net heat loss per unit length considering 1m length in W\n", +"q = ((A*sigma)*epsilon)*(T1^4-T2^4)\n", +"\n", +"//From eq. 1.21 radiation heat transfer coefficient in W/m2-K is\n", +"disp('Radiation heat transfer coefficient in W/m2-K is')\n", +"//Radiation heat transfer coefficient in W/m2-K \n", +"hr = ((epsilon*sigma)*(T1^4-T2^4))/(T1-T2)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 1.5: Heat_Loss_From_a_Composite_Wall.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 1 Example # 1.5 ')\n", +"\n", +"//Thickness of inside steel in m and thermal conductivity in W/m-k\n", +"t1 = 0.005;\n", +"k1 = 40;\n", +"//Thickness of outside brick in m and thermal conductivity in W/m-k\n", +"t2 = 0.1;\n", +"k2 = 2.5;\n", +"\n", +"//Inside temperature in C\n", +"T1 = 900;\n", +"//Outside temperature in C\n", +"To = 460;\n", +"\n", +"//Assuming the condition of steady state and using Eq. 1.24\n", +"disp('The rate of heat loss per unit area in W/m2 is')\n", +"//The rate of heat loss per unit area in W/m2 \n", +"qk = (T1-To)/(t1/k1+t2/k2)\n", +"\n", +"disp('Temperature at the interface in K is given as')\n", +"//Temperature at the interface in K\n", +"T2 = T1-(qk*t1)/k1" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 1.6: Analysis_of_Aluminium_Plates.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 1 Example # 1.6 ')\n", +"\n", +"//Thermal conductivity of aluminium in W/m-K\n", +"k = 240;\n", +"//Thickness of each plate in m\n", +"t = 0.01;\n", +"//Temperature at the surfaces of plates in C is given as\n", +"Ts1 = 395;\n", +"Ts3 = 405;\n", +"//From Table 1.6 the contact resistance at the interface in K/W is\n", +"R2 = 0.000275;\n", +"//Thermal resistance of the plates in K/W is\n", +"R1 = t/k;\n", +"R3 = t/k;\n", +"\n", +"disp('Heat flux in W/m2-K is')\n", +"//Heat flux in W/m2-K\n", +"q = (Ts3-Ts1)/(R1+R2+R3)\n", +"\n", +"//Since the temperature drop in each section of this one-dimensional system is propor-tional to the resistance.\n", +"\n", +"disp('Temperature drop due to contact resistance in degree C is')\n", +"//Temperature drop due to contact resistance in degree C\n", +"deltaT = (R2/(R1+R2+R3))*(Ts3-Ts1)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 1.7: Heat_flow_in_Firebrick_Steel_System.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 1 Example # 1.7 ')\n", +"\n", +"//Because of symmetry, we need to calculate for only one half of the system\n", +"\n", +"//Thickness of firebrick in inches\n", +"L1 = 1;\n", +"//Thermal conductivity of firebrick in Btu/h-ft-F\n", +"kb = 1;\n", +"//Thickness of steel plate in inches\n", +"L3 = 1/4;\n", +"//Thermal conductivity of steel in Btu/h-ft-F\n", +"ks = 30;\n", +"//Average height of asperities in inches is given as\n", +"L2 = 1/32;\n", +"//Temperature difference between the steel plates in F is\n", +"deltaT = 600;\n", +"\n", +"\n", +"//The thermal resistance of the steel plate is, on the basis of a unit wall area, equal to\n", +"R3 = L3/(12*ks);//12 is added to convert ft to in\n", +"\n", +"//The thermal resistance of the brick asperities is, on the basis of a unit wall area, equal to\n", +"R4 = L2/((0.3*12)*kb);//Considering the 30 percent area\n", +"\n", +"//At temperature of 300F, thermal conductivity of air in Btu/h-ft-F is\n", +"ka = 0.02;\n", +"\n", +"// Thermal resistance of the air trapped between the asperities, is, on the basis of a unit area, equal to\n", +"R5 = L2/((0.7*12)*ka);//Considering the other 70 percent area\n", +"\n", +"//Since R4 and R5 are in parallel, so there combined resistance is\n", +"R2 = (R4*R5)/(R4+R5);\n", +"\n", +"//The thermal resistance of half of the solid brick is\n", +"R1 = L1/(12*kb);\n", +"\n", +"//The overall unit conductance for half the composite wall in Btu/h-ft2-F is then\n", +"kk = 0.5/(R1+R2+R3);\n", +"\n", +"disp('The rate of heat flow per unit area in Btu/h-ft2 is')\n", +"//The rate of heat flow per unit area in Btu/h-ft2\n", +"q = kk*deltaT" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 1.8: Heat_Dissipation_in_Instrument_Circuit.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 1 Example # 1.8 ')\n", +"\n", +"//Length for heat transfer for stainless steel in m\n", +"Lss = 0.1;\n", +"\n", +"//Area for heat transfer for stainless steel in m2\n", +"A = 0.01;\n", +"\n", +"//Thermal conductivity for stainless steel in W/m-K\n", +"kss = 144;\n", +"\n", +"//Length for heat transfer for Duralumin in m\n", +"La1 = 0.02;\n", +"\n", +"//Area for heat transfer for Duralumin in m2\n", +"A = 0.01;\n", +"\n", +"//Thermal conductivity for Duralumin in W/m-K\n", +"ka1 = 164;\n", +"\n", +"//Resistance in case of steel in K/W\n", +"Rk1 = Lss/(A*kss);\n", +"\n", +"//Resistance in case of Duralumin in K/W\n", +"Rk2 = La1/(A*ka1);\n", +"\n", +"//From Fig. 1.20, contact resistance in K/W\n", +"Ri = 0.05;\n", +"\n", +"//Total resistance to heat transfer in K/W\n", +"Rtotal = Rk1+Rk2+Ri;\n", +"\n", +"//Temperature diff. is given in K\n", +"deltaT = 40;\n", +"\n", +"disp('Maximum allowable rate of heat dissipation in W is')\n", +"//Maximum allowable rate of heat dissipation in W\n", +"q = deltaT/Rtotal" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 1.9: Heat_Transfer_Through_Brick_Wall.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 1 Example # 1.9 ')\n", +"\n", +"//Cross sectional area in m2\n", +"A = 1;\n", +"//Heat transfer coefficient on hot side in W/m2-K\n", +"hchot = 10;\n", +"//Heat transfer coefficient on cold side in W/m2-K\n", +"hccold = 40;\n", +"\n", +"//Length for heat transfer in m\n", +"L = 0.1;\n", +"//Thermal conductivity in W/m-K\n", +"k = 0.7;\n", +"\n", +"//Resistances in K/w\n", +"R1 = 1/(hchot*A);\n", +"R2 = L/(k*A);\n", +"R3 = 1/(hccold*A);\n", +"\n", +"//Total resistance\n", +"Rtotal = R1+R2+R3;\n", +"\n", +"//Temperature on hot side in K\n", +"T1 = 330;\n", +"//Temperature on cold side in K\n", +"T2 = 270;\n", +"\n", +"disp('Rate of heat transfer per unit area in W is')\n", +"//Rate of heat transfer per unit area in W\n", +"q = (T1-T2)/(R1+R2+R3)" + ] + } +], +"metadata": { + "kernelspec": { + "display_name": "Scilab", + "language": "scilab", + "name": "scilab" + }, + "language_info": { + "file_extension": ".sce", + "help_links": [ + { + "text": "MetaKernel Magics", + "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md" + } + ], + "mimetype": "text/x-octave", + "name": "scilab", + "version": "0.7.1" + } + }, + "nbformat": 4, + "nbformat_minor": 0 +} diff --git a/Principles_Of_Heat_Transfer_by_F_Kreith/10-Heat_Transfer_with_Phase_Change.ipynb b/Principles_Of_Heat_Transfer_by_F_Kreith/10-Heat_Transfer_with_Phase_Change.ipynb new file mode 100644 index 0000000..81d4e69 --- /dev/null +++ b/Principles_Of_Heat_Transfer_by_F_Kreith/10-Heat_Transfer_with_Phase_Change.ipynb @@ -0,0 +1,466 @@ +{ +"cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Chapter 10: Heat Transfer with Phase Change" + ] + }, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 10.1: Water_Boiling_on_Steel_Surface.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat transfer, Seventh Edition, Frank Kreith, Raj M Manglik and Mark S Bohn, Chapter 10, Example 1')\n", +"//Surface temperature of polished stainless steel surface in degree celcius\n", +"T_s=106;\n", +"//Boiling point of water under at atmospheric pressure in degree celcius\n", +"T_b=100;\n", +"//Value of empirical constant\n", +"C_sf=0.0132;\n", +"//latent heat of vaporization in J/kg\n", +"h_fg=2.25e6;\n", +"//gravitational acceleration in m/s^2\n", +"g=9.81;\n", +"//Value of proportionality factor in British Gravitational system\n", +"g_c=1;\n", +"//density of saturated liquid in kg/m^3\n", +"rho_l=962;\n", +"//density of saturated vapor in kg/m^3\n", +"rho_v=0.60;\n", +"//specific heat of saturated liquid in J/kg K\n", +"c_l=4211;\n", +"//prandtl number of saturated liquid\n", +"Pr_l=1.75;\n", +"//surface tension of the liquid-to-vapor interface in N/m\n", +"sigma=58.8e-3;\n", +"// viscosity of the liquid in kg/ms\n", +"mu_l=2.77e-4;\n", +"//Excess temperature in degree Celcius\n", +"delta_Tx= T_s-T_b;\n", +"\n", +"disp('Heat flux from the surface to the water in W/m^2')\n", +"//Heat flux in W./m2\n", +"q=(c_l*delta_Tx/(C_sf*h_fg*Pr_l))^3*mu_l*h_fg*sqrt((g*(rho_l-rho_v))/(g_c*sigma))\n", +"\n", +"disp('Critical heat flux in W/m^2')\n", +"//Heat flux in W./m2\n", +"q_maxZ=(%pi/24)*sqrt(rho_v)*h_fg*(sigma*g*(rho_l-rho_v)*g_c)^0.25\n", +"\n", +"disp('At 6°C excess temperature the heat flux is less than the critical value; therefore nucleate pool boiling exists')\n", +"disp('For the Teflon-coated stainless steel surface, heat flux in W/m^2')\n", +"//Heat flux in W./m2\n", +"q=29669*(C_sf/0.0058)^3\n", +"disp('Thus for Teflon-coated stainless steel surface there is a remarkable increase in heat flux; however, it is still below the critical value.')" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 10.2: Water_Boiling_on_Polished_Surface.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat transfer, Seventh Edition, Frank Kreith, Raj M Manglik and Mark S Bohn, Chapter 10, Example 2')\n", +"//density of saturated liquid in kg/m^3\n", +"rho_l=962;\n", +"//gravitational acceleration in m/s^2\n", +"g=9.8;\n", +"//latent heat of vaporization in J/kg\n", +"h_fg=2250000;\n", +"//density of saturated vapor in kg/m^3\n", +"rho_v=0.60;\n", +"//Surface temperature of polished stainless steel surface in degree celcius\n", +"T_s=400;\n", +"//Value of proportionality factor in British Gravitational system\n", +"g_c=1;\n", +"//Boiling point of water under at atmospheric pressure in degree celcius\n", +"T_b=100;\n", +"//surface tension of the liquid-to-vapor interface in N/m\n", +"sigma=58.8e-3;\n", +"//Excess temperature in degree Celcius\n", +"delta_Tx= T_s-T_b;\n", +"//Wavelength in m from eq. 10.7\n", +"lamda=2*%pi*sqrt(g_c*sigma/(g*(rho_l-rho_v)));\n", +"//Thermal conductivity in W/mK\n", +"k_c=0.0249;\n", +"//Absolute viscosity in Ns/m^2\n", +"mu_c=12.1e-6;\n", +"//Specific heat in J/kg K\n", +"c_pc=2034;\n", +"//Heat transfer coefficient due to conduction alone in W/m^2 K\n", +"h_c=(0.59)*(((g*(rho_l-rho_v)*rho_v*(k_c^3)*(h_fg+(0.68*c_pc*delta_Tx)))/(lamda*mu_c*delta_Tx))^0.25); // expression obtained assuming diameter D tending to infinity\n", +"//Emissivity\n", +"epsilon_s= 0.05; //since surface is polished and hence heat transfer coefficient due to radiation is negligible\n", +"disp('Heat flux in W/m^2')\n", +"//Heat flux in W/m^2\n", +"q= h_c*delta_Tx" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 10.3: Flow_of_n_Butyl_Alcohol.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat transfer, Seventh Edition, Frank Kreith, Raj M Manglik and Mark S Bohn, Chapter 10, Example 3')\n", +"//Flow rate of n-butyl alcohol in kg/hr\n", +"m=161;\n", +"//Internal diameter of copper tube in meters\n", +"D=0.01;\n", +"//Tube wall temperature in degree C\n", +"T=140;\n", +"//surface tension in N/m\n", +"sigma=0.0183;\n", +"//Heat of vaporization in J/kg\n", +"h_fg=591500;\n", +"//atmospheric pressure boiling point in degree C\n", +"T_sat=117.5;\n", +"// saturation pressure corresponding to a saturation temperature of 140°C in atm\n", +"P_sat=2;\n", +"//Density of vapor in kg/m^3\n", +"rho_v=2.3;\n", +"//Viscosity of vapor in kg/m s\n", +"mu_v=.0143e-3;\n", +"//Property values for n-butyl alcohol are taken from Appendix 2, Table 19\n", +"//Density in kg/m^3\n", +"rho_l=737;\n", +"//Absolute viscosity in Ns/m^2\n", +"mu_l=0.39e-3;\n", +"//Specific heat in J/kg K\n", +"c_l=3429;\n", +"//Prandtl number\n", +"Pr_l=8.2;\n", +"//Thermal conductivity in W/m K\n", +"k_l=0.13;\n", +"//Empirical constant\n", +"C_sf=0.00305;// Value taken from table 10.1\n", +"//Mass velocity in kg/m^2 s\n", +"G=(m/3600)*(4/(%pi*0.01^2));\n", +"//Reynolds number for liquid flow\n", +"Re_D=(G*D)/mu_l;\n", +"//The contribution to the heat transfer coefficient due to the two-phase annular flow is [(0.023)*(14590)^0.8*(8.2)^0.4*16.3*(1-x)^0.8*F]\n", +"//Since the vapor pressure changes by 1 atm over the temperature range from saturation temperature to 140°C,so saturation pressure in N/m^2\n", +"delta_p_sat=101300;\n", +"//Therefore the contribution to the heat transfer coefficient from nucleate boiling is\n", +"//h_b= 0.00122*[(0.163^0.79*3429^0.45*737^0.49*1^0.25)/(0.0183^0.5*0.39e-3^0.29*591300^0.24*2.3^0.24)]*(140-117.5)^0.24*(101300)^0.75*S\n", +"//or h_b= 8393S\n", +"//Now 1/Xtt will be calculated by\n", +"//1/Xtt=12.86*(x/(1-x))^0.9\n", +"//Now a table is prepared showing stepwise calculations that track the increase in quality, from x=0 to x=0.5,assuming that the steps delta x are small enough that the heat flux and other parameters are reasonably constant in that step\n", +"disp('The tube length required to reach 50% quality is 1.35 m')" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 10.4: Heat_Transfer_Coefficients_For_Tube.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat transfer, Seventh Edition, Frank Kreith, Raj M Manglik and Mark S Bohn, Chapter 10, Example 4')\n", +"//Outer diameter of the tube in meters\n", +"D=0.013;\n", +"//Acceleration due to gravity in m/s^2\n", +"g=9.81;\n", +"//Length of the tube in meters\n", +"L=1.5;\n", +"//Temperature of saturated vapour in Kelvin\n", +"T_sv=349;\n", +"//Average tube wall temperature in Kelvin\n", +"T_s=325;\n", +"//Average temperature of the condensate film in degree K\n", +"Tf=(T_sv+T_s)/2;\n", +"//Thermal conductivity of liquid in W/m-K\n", +"k_l=0.661;\n", +"//Viscosity of liquid in N s/m^2\n", +"mu_l=4.48e-4;\n", +"//Dendity of liquid in kg/m^3\n", +"rho_l=980.9;\n", +"//Specific heat of liquid in J/kg K\n", +"c_pl=4184;\n", +"//Latent heat of condensation in J/kg\n", +"h_fg=2.349e6;\n", +"//Density of vapor in kg/m^3\n", +"rho_v=0.25;\n", +"//Modified latent heat of condensation in J/kg\n", +"h_fg_dash=h_fg+(3/8)*c_pl*(T_sv-T_s);\n", +"\n", +"disp('Heat transfer coefficient for tube in horizontal position in W/m^2 K')\n", +"//Heat transfer coefficient in W/m2K\n", +"h_c_bar=0.725*(((rho_l*(rho_l-rho_v)*g*h_fg_dash*k_l^3)/(D*mu_l*(T_sv-T_s)))^0.25)\n", +"disp('Heat transfer coefficient for tube in vertical position in W/m^2 K')\n", +"////Heat transfer coefficient in W/m2K\n", +"h_c_bar=0.943*(((rho_l*(rho_l-rho_v)*g*h_fg_dash*k_l^3)/(mu_l*(T_sv-T_s)))^0.25)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 10.5: Condensate_Flow_Determination.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat transfer, Seventh Edition, Frank Kreith, Raj M Manglik and Mark S Bohn, Chapter 10, Example 5')\n", +"//Acceleration due to gravity in m/s^2\n", +"g=9.81;\n", +"//Length of the tube in meters\n", +"L=1.5;\n", +"//Temperature of saturated vapour in Kelvin\n", +"T_sv=349;\n", +"//Average tube wall temperature in Kelvin\n", +"T_s=325;\n", +"//Average temperature of the condensate film in Kelvin\n", +"Tf=(T_sv+T_s)/2;\n", +"//Thermal conductivity of liquid in W/m-K\n", +"k_l=0.661;\n", +"//Viscosity of liquid in N s/m^2\n", +"mu_l=4.48e-4;\n", +"//Dendity of liquid in kg/m^3\n", +"rho_l=980.9;\n", +"//Specific heat of liquid in J/kg K\n", +"c_pl=4184;\n", +"//Latent heat of condensation in J/kg\n", +"h_fg=2.349e6;\n", +"//Density of vapor in kg/m^3\n", +"rho_v=0.25;\n", +"//Modified latent heat of condensation in J/kg\n", +"h_fg_dash=h_fg+(3/8)*c_pl*(T_sv-T_s);\n", +"\n", +"disp('Reynolds number at the lower edge')\n", +"//Reynolds number\n", +"Re=(4/3)*(((4*k_l*L*(T_sv-T_s)*rho_l^(2/3)*g^(1/3))/(mu_l^(5/3)*h_fg_dash))^0.75)\n", +"disp('Since the Reynolds number at the lower edge of the tube is below 2000, the flow of the condensate is laminar')" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 10.6: Heat_Transport_Capability_of_Water.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat transfer, Seventh Edition, Frank Kreith, Raj M Manglik and Mark S Bohn, Chapter 10, Example 6')\n", +"//Length of Heat pipe in meters\n", +"L_eff=0.30;\n", +"//Temperature of the heat pipe in degree celcius\n", +"T=100;\n", +"//Diameter of the heat pipe in meters\n", +"D=1e-2;\n", +"//Density of water at 100 degree celcius in k/m^3\n", +"rho=958;\n", +"//Viscosity of water in N s/m^2\n", +"mu=279e-6;\n", +"//surface tension of the liquid-to-vapor interface in N/m\n", +"sigma=58.9e-3;\n", +"//latent heat of vaporization in J/kg\n", +"h_fg=2.26e6;\n", +"//Inclination angle in degree\n", +"theta=30;\n", +"//Acceleration due to gravity in meter/sec^2\n", +"g=9.81;\n", +"//Wire diameter for wick in metres\n", +"d=0.0045e-2;\n", +"//So thickness of four layers of wire mesh\n", +"t=4*d;\n", +"//Area of the wick in m^2\n", +"Aw=%pi*D*t;\n", +"//For phosphorus-bronze,heat pipe wick pore size in meters\n", +"r=0.002e-2;\n", +"//For phosphorus-bronze,heat pipe wick permeability in m^2\n", +"K=0.3e-10;\n", +"disp('Maximum liquid flow rate in kg/sec')\n", +"//flow rate in kg/sec\n", +"m_max=((2*sigma/r)-rho*g*L_eff*sind(theta))*((rho*Aw*K)/(mu*L_eff))\n", +"disp('Maximum heat transport capability in Watt')\n", +"//heat transport capability in W\n", +"q_max=m_max*h_fg" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 10.7: Forming_of_Ice_Layer.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat transfer, Seventh Edition, Frank Kreith, Raj M Manglik and Mark S Bohn, Chapter 10, Example 7')\n", +"//Temperature of the brine spray used for internal refrigeration in degree celcius\n", +"T_inf=-11;\n", +"//Required thickness of ice layer in meters\n", +"epsilon= 0.0025;\n", +"//Water-liquid temperature in degree celcius\n", +"T1=4.4;\n", +"//Liquid-surface conductance in W/m^2 K\n", +"h_epsilon=57;\n", +"//Conductance between brine and ice(including metal wall) in W/m^2 K\n", +"h_not=570;\n", +"//Latent heat of fusion for ice in J/Kg\n", +"Lf=333700;\n", +"//Density for ice in Kg/m^3\n", +"rho=918;\n", +"//Thermal conductivity for ice in W/m K\n", +"k=2.32;\n", +"//Freezing point temperature in degree K\n", +"Tfr=0;\n", +"//Dimensionless R, T, epsilon and t are as follows\n", +"//R plus parameter \n", +"R_plus= h_epsilon/h_not;\n", +"//T plus parameter\n", +"T_plus= (T1-Tfr)/(Tfr-T_inf);\n", +"//Epsilon plus parameter\n", +"Epsilon_plus= h_not*epsilon/k;\n", +"//t plus parameter\n", +"t_plus=(Epsilon_plus/(R_plus*T_plus))-((1/(R_plus*T_plus)^2)*log(1+(R_plus*T_plus*Epsilon_plus/(1+R_plus*T_plus))))\n", +"\n", +"disp('Time taken for 0.25cm thick ice layer deposition in sec')\n", +"//time in seconds\n", +"t=t_plus*rho*Lf*k/((h_not)^2*(Tfr-T_inf))" + ] + } +], +"metadata": { + "kernelspec": { + "display_name": "Scilab", + "language": "scilab", + "name": "scilab" + }, + "language_info": { + "file_extension": ".sce", + "help_links": [ + { + "text": "MetaKernel Magics", + "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md" + } + ], + "mimetype": "text/x-octave", + "name": "scilab", + "version": "0.7.1" + } + }, + "nbformat": 4, + "nbformat_minor": 0 +} diff --git a/Principles_Of_Heat_Transfer_by_F_Kreith/2-Heat_Conduction.ipynb b/Principles_Of_Heat_Transfer_by_F_Kreith/2-Heat_Conduction.ipynb new file mode 100644 index 0000000..a580f89 --- /dev/null +++ b/Principles_Of_Heat_Transfer_by_F_Kreith/2-Heat_Conduction.ipynb @@ -0,0 +1,872 @@ +{ +"cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Chapter 2: Heat Conduction" + ] + }, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 2.10: Transient_Response_of_Thermocouple.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 2 Example # 2.10 ')\n", +"\n", +"//Diameter of copper wire in m\n", +"D = 0.1/100;\n", +"//Initial temperature in degree C\n", +"To = 150;\n", +"//Final surrounding temperature in degree C of air and water\n", +"Tinfinity = 40;\n", +"\n", +"//From table 12, appendix 2, we get the following data values for copper\n", +"//Thermal conductivity in W/mK\n", +"k = 391;\n", +"//Specific heat in J/kgK\n", +"c = 383;\n", +"//Density in kg/m3\n", +"rho = 8930;\n", +"\n", +"//Surface area of wire per unit length in m\n", +"A = %pi*D;\n", +"//Volume of wire per unit length in m2\n", +"V = ((%pi*D)*D)/4;\n", +"\n", +"//Heat transfer coefficient in the case of water in W/m2K\n", +"h = 80;\n", +"//Biot number in water\n", +"bi = (h*D)/(4*k);\n", +"//The temperature response is given by Eq. (2.84)\n", +"\n", +"//For water Bi*Fo is 0.0936t\n", +"//For air Bi*Fo is 0.0117t\n", +"\n", +"for i = 1:130\n", +" //Position of grid\n", +" x(1,i) = i;\n", +" // Temperature of water in degree C\n", +" Twater(1,i) = Tinfinity+(To-Tinfinity)*exp(-0.0936*i);\n", +" // Temperature of air in degree C\n", +" Tair(1,i) = Tinfinity+(To-Tinfinity)*exp(-0.0117*i);\n", +"end;\n", +"//Plotting curve\n", +"plot(x,Twater,'--r')\n", +"set(gca(),'auto_clear','off')\n", +"//Plotting curve\n", +"plot(x,Tair)\n", +"//Labelling axis\n", +"xlabel('time')\n", +"ylabel('temperature')\n", +"disp('Temperature drop in water is more than that of air')" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 2.11: Minimum_Depth_of_Water_Mains.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 2 Example # 2.11 ')\n", +"\n", +"//Initial temperature of soil in degree C\n", +"Ti = 20;\n", +"//Surface temperature of soil\n", +"Ts = -15;\n", +"//Critical temperature (Freezing temperature) in degree C\n", +"Tc = 0;\n", +"//Time in days\n", +"t = 60;\n", +"//Density of soil in kg/m3\n", +"rho = 2050;\n", +"//Thermal conductivity of soil in W/mK\n", +"k = 0.52;\n", +"//Specific heat in J/kgK\n", +"c = 1840;\n", +"//Diffusivity in m2/sec\n", +"alpha = k/(rho*c);\n", +"\n", +"//Finding the value of following to proceed further\n", +"//Z value\n", +"z = (Tc-Ts)/(Ti-Ts);\n", +"\n", +"//From table 43, it corresponds to an error function value of 0.4,\n", +"//proceeding\n", +"\n", +"disp('Minimum depth at which one must place a water main below the surface to avoid freezing in m is')\n", +"//Minimum depth at which one must place a water main below the surface to avoid freezing in m\n", +"xm = (0.4*2)*((((alpha*t)*24)*3600)^0.5)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 2.12: Steel_Component_Fabrication_Process.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 2 Example # 2.12 ')\n", +"\n", +"//Length of steel component in m\n", +"L = 2;\n", +"//Radius of steel component in m\n", +"ro = 0.1;\n", +"//Thermal conductivity of steel in W/mK\n", +"k = 40;\n", +"//Thermal diffusivity in m2/s\n", +"alpha = 0.00001;\n", +"//Initital temperature in degree C\n", +"Ti = 400;\n", +"//Surrounding temperature in degree C\n", +"Tinfinity = 50;\n", +"//Heat transfer coefficient in W/m2K\n", +"h = 200;\n", +"//time of immersion in mins\n", +"t = 20;\n", +"\n", +"//Since the cylinder has a length 10 times the diameter, we can neglect end\n", +"//effects.\n", +"\n", +"//Calculating biot number\n", +"bi = (h*ro)/k;\n", +"if bi>0.1 then\n", +" //Calculating fourier number\n", +" fo = ((alpha*t)*60)/(ro*ro);\n", +" //The initial amount of internal energy stored in the cylinder per unit\n", +" //length in Ws/m\n", +" Q = ((((k*%pi)*ro)*ro)*(Ti-Tinfinity))/alpha;\n", +"\n", +" //The dimensionless centerline temperature for 1/Bi= 2.0 and Fo= 1.2 from\n", +" //Fig. 2.43(a)\n", +" //Centreline temperature in degree C\n", +" T = Tinfinity+0.35*(Ti-Tinfinity);\n", +" disp('Centreline temperature in degree C is')\n", +" T\n", +" //The surface temperature at r/r0= 1.0 and t= 1200 s is obtained from Fig. 2.43(b) in terms of the centerline temperature\n", +" //Surface temperature in degree C\n", +" Tr = Tinfinity+0.8*(T-Tinfinity);\n", +" disp('Surface temperature in degree C is')\n", +" Tr\n", +" //Then the amount of heat transferred from the steel rod to the water can be obtained from Fig. 2.43(c). Since Q(t)/Qi= 0.61,\n", +" disp('The heat transferred to the water during the initial 20 min in Wh is')\n", +" //The heat transferred to the water during the initial 20 min in Wh\n", +" Q = ((0.61*L)*Q)/3600\n", +"end;" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 2.13: Analysis_of_Concrete_Wall.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 2 Example # 2.13 ')\n", +"\n", +"//Thickness of wall in m\n", +"L = 0.5;\n", +"//Initial temperature in degree C\n", +"Ti = 60;\n", +"//Combustion gas (Surrounding) temperature in degree C\n", +"Tinfinity = 900;\n", +"//Heat transfer coefficient in W/m2K\n", +"h = 25;\n", +"//Thermal conductivity in W/mk\n", +"k = 1.25;\n", +"//Specific heat in J/KgK\n", +"c = 837;\n", +"//Density in kg/m3\n", +"rho = 500;\n", +"//Thermal diffusivity in m2/s\n", +"alpha = 0.000003;\n", +"//Required temperature to achieve in degree C\n", +"Ts = 600;\n", +"\n", +"//Calculating temperature ratio\n", +"z = (Ts-Tinfinity)/(Ti-Tinfinity);\n", +"//Reciprocal biot number\n", +"bi = k/(h*L);\n", +"\n", +"\n", +"//From Fig. 2.42(a) we find that for the above conditions the Fourier number= 0.70 at the midplane.\n", +"//Time in hours\n", +"t = ((0.7*L)*L)/alpha;\n", +"disp('Time in hours is')\n", +"//Time in hours\n", +"t = t/3600\n", +"\n", +"//The temperature distribution in the wall 16 h after the transient was\n", +"//initiated can be obtained from Fig. 2.42(b) for various values of x/L\n", +"\n", +"disp('Temperature distribution in degree C is')\n", +"disp(' (x/l) = 1.00 0.80 0.60 0.40 0.20')\n", +"disp('Fraction = 0.13 0.41 0.64 0.83 0.96')\n", +"\n", +"//The heat transferred to the wall per square meter of surface area during\n", +"//the transient can be obtained from Fig. 2.42(c).\n", +"disp('Heat transfer in J/m2 is')\n", +"//Heat transfer in J/m2\n", +"Q = ((c*rho)*L)*(Ti-Tinfinity)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 2.14: Cylinder_Places_in_Hot_Oven.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 2 Example # 2.14 ')\n", +"\n", +"//Radius of cylinder in m\n", +"ro = 0.05;\n", +"//Length of cylinder in m\n", +"L = 0.16;\n", +"//Thermal conductivity in W/mK\n", +"k = 0.5;\n", +"//Thermal diffusivity in m2/s\n", +"alpha = 0.0000005;\n", +"//Initial temperature in degree C\n", +"Ti = 20;\n", +"//Surrounding temperature in degree C\n", +"Tinfinity = 500;\n", +"//Heat transfer coefficient in W/m2K\n", +"h = 30;\n", +"//Time in mins\n", +"t = 30;\n", +"\n", +"//Biot number\n", +"bi = (h*ro)/k;\n", +"//Fourier number\n", +"fo = ((alpha*t)*60)/((L*L)/4);\n", +"\n", +"//From fig. 2.42(a)\n", +"//Po\n", +"P0 = 0.9;\n", +"//From fig. 2.42(a) and (b)\n", +"//Pl\n", +"PL = 0.243;\n", +"//From fig. 2.43(a)\n", +"//Co\n", +"C0 = 0.47;\n", +"//From fig. 2.43(a) and (b)\n", +"//Cr\n", +"CR = 0.155;\n", +"disp('Minimum temperature in degree C')\n", +"//Minimum temperature in degree C\n", +"Tmin = Tinfinity+((Ti-Tinfinity)*P0)*C0" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 2.1: Calculation_of_Heat_Transfer_Coeffcient.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 2 Example # 2.1 ')\n", +"\n", +"//Heat generation rate in W/m3\n", +"qg = 1000000;\n", +"//Length along which heat will be dissipated in m (thickness)\n", +"L = 0.01;\n", +"//Thermal conductivity at the required temperature in W/mK\n", +"k = 64;\n", +"\n", +"//Temperature of surrounding oil in degree C\n", +"Tinfinity = 80;\n", +"//Temperature of heater in degree C to be maintained\n", +"T1 = 200;\n", +"\n", +"disp('heat transfer coefficient in W/m2K from a heat balance')\n", +"//Heat transfer coefficient in W/m2K\n", +"h = ((qg*L)/2)/(T1-Tinfinity)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 2.2: Insulated_vs_Uninsulated_Copper_Pipe.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 2 Example # 2.2 ')\n", +"\n", +"disp('Case of Uninsualted pipe')\n", +"//Calculating resistance to heat flow at internal surface\n", +"\n", +"//Internal radius in m\n", +"ri = 0.05;\n", +"//Heat transfer coefficient at inner surface for steam condensing in W/m2K\n", +"hci = 10000;\n", +"//Resistance in mK/W\n", +"R1 = 1/(((2*%pi)*ri)*hci);\n", +"\n", +"//Calculating resistance to heat flow at external surface\n", +"\n", +"//External radius in m\n", +"ro = 0.06;\n", +"//Heat transfer coefficient at outer surface in W/m2K\n", +"hco = 15;\n", +"//Resistance in mK/W\n", +"R3 = 1/(((2*%pi)*ro)*hco);\n", +"\n", +"//Calcualting resistance to heat flow due to pipe\n", +"\n", +"//Thermal conductivity of pipe in W/mK\n", +"kpipe = 400;\n", +"//Resistance in mK/W\n", +"R2 = log(ro/ri)/((2*%pi)*kpipe);\n", +"\n", +"//Temperatures of steam(pipe) and surrounding(air) in degree C\n", +"Ts = 110;\n", +"Tinfinity = 30;\n", +"\n", +"disp('Heat loss from uninsulated pipe in W/m is therefore')\n", +"//Heat loss from uninsulated pipe in W/m \n", +"q = (Ts-Tinfinity)/(R1+R2+R3)\n", +"\n", +"\n", +"disp('Case of insulated pipe')\n", +"//Calculating additional resistance between outer radius and new outer\n", +"//radius\n", +"\n", +"//Thermal conductivity of insulation in W/mK\n", +"k = 0.2;\n", +"//New outer radius in m\n", +"r3 = 0.11;\n", +"//Resistance in mK/W\n", +"R4 = log(r3/ro)/((2*%pi)*k);\n", +"\n", +"//Calculating new outer resistance\n", +"R0 = 1/(((2*%pi)*r3)*hco);\n", +"\n", +"\n", +"disp('Heat loss from insulated pipe in W/m is therefore')\n", +"//Heat loss from insulated pipe in W/m\n", +"q = (Ts-Tinfinity)/(R1+R2+R4+R0)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 2.3: Hot_Fluid_Flowing_Through_Pipe.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 2 Example # 2.3 ')\n", +"\n", +"//Outer radius in m\n", +"ro = 0.02;\n", +"//Inner radius in m\n", +"ri = 0.015;\n", +"//Thermal conductivity of plastic in W/mK\n", +"k = 0.5;\n", +"//Internal convection heat transfer coefficient in W/m2K\n", +"hc1 = 300;\n", +"//Temperature of fluid in pipe in degree C\n", +"Thot = 200;\n", +"//Temperature of outside in degree C\n", +"Tcold = 30;\n", +"//External convection heat transfer coefficient in W/m2K\n", +"hc0 = 10;\n", +"\n", +"disp('Overall heat transfer coefficient in W/m2K is')\n", +"//Overall heat transfer coefficient in W/m2K\n", +"U0 = 1/(ro/(ri*hc1)+(ro*log(ro/ri))/k+1/hc0)\n", +"\n", +"disp('The heat loss per unit length in W/m is')\n", +"//The heat loss per unit length in W/m\n", +"q = (((U0*2)*%pi)*ro)*(Thot-Tcold)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 2.4: Boiling_Off_Of_Nitrogen.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 2 Example # 2.4 ')\n", +"\n", +"//Temperature of liquid nitrogen in degree K\n", +"Tnitrogen = 77;\n", +"//Radius of container in m\n", +"ri = 0.25;\n", +"//Temperature of surrounding air in degree K\n", +"Tinfinity = 300;\n", +"//Thermal conductivity of insulating silica powder in W/mK\n", +"k = 0.0017;\n", +"//Outer radius of container with insulation in m\n", +"ro = 0.275;\n", +"//Latent heat of vaporization of liquid nitrogen in J/kg\n", +"hgf = 200000;\n", +"//convection coefficient at outer surface in W/m2K\n", +"hco = 20;\n", +"\n", +"//Calcaulting heat transfer to nitrogen\n", +"q = (Tinfinity-Tnitrogen)/(1/((((4*%pi)*ro)*ro)*hco)+(ro-ri)/((((4*%pi)*k)*ro)*ri));\n", +"\n", +"disp(' rate of liquid boil-off of nitrogen per hour is')\n", +"//rate of liquid boil-off of nitrogen per hour\n", +"m = (3600*q)/hgf" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 2.5: Analysis_of_Nuclear_Reactor.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 2 Example # 2.5 ')\n", +"\n", +"//Heat generation rate in W/m3\n", +"qg = 75000000;\n", +"//Outer radius of rods in m\n", +"ro = 0.025;\n", +"//Temperature of water in degree C\n", +"Twater = 120;\n", +"//Thermal cinductivity in W/mk\n", +"k = 29.5\n", +"//Heat transfer coefficient in W/m2K\n", +"hco = 55000;\n", +"\n", +"//Since rate of flow through the surface of the rod equals the rate of internal heat generation\n", +"//and\n", +"//The rate of heat flow by conduction at the outer surface equals the rate\n", +"//of heat flow by convection from the surface to the water\n", +"\n", +"//Surface Temperature in degree C\n", +"T0 = (qg*ro)/(2*hco)+Twater;\n", +"\n", +"disp('Maximum temperature in degree C')\n", +"//Maximum temperature in degree C\n", +"Tmax = T0+((qg*ro)*ro)/(4*k)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 2.6: Analysis_of_Copper_Pin_Fin.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 2 Example # 2.6 ')\n", +"\n", +"//diameter of fin in m\n", +"d = 0.0025;\n", +"//Perimeter in m\n", +"P = %pi*d;\n", +"//Area in m2\n", +"A = ((%pi*d)*d)/4;\n", +"//Surface temperature in degree C\n", +"Ts = 95;\n", +"//Ambient temperature in degree c\n", +"Tinfinity = 25;\n", +"//Heat transfer coefficient in W/m2K\n", +"hc = 10;\n", +"//From table 12, value of thermal conductivity in W/mK\n", +"k = 396;\n", +"\n", +"disp('Case of an infinitely long fin')\n", +"disp('Heat loss for the “infintely long” fin in W is')\n", +"//Heat loss for the “infintely long” fin in W\n", +"qfin = ((((hc*P)*k)*A)^0.5)*(Ts-Tinfinity)\n", +"\n", +"disp('Case 2: Fin length of 2.5cm')\n", +"//Length in cm\n", +"L = 2.5/100;\n", +"//Parameter m\n", +"m = ((hc*P)/(k*A))^0.5;\n", +"disp('Heat loss in this case in W is')\n", +"//Heat loss in this case in W\n", +"qfin = qfin*((sinh(m*L)+(hc/(m*k))*cosh(m*L))/(cosh(m*L)+(hc/(m*k))*sinh(m*L)))\n", +"\n", +"disp('For the two solutions to be within 5%')\n", +"//((sinh(m*L)+(hc/(m*k))*cosh(m*L))/(cosh(m*L)+(hc/(m*k))*sinh(m*L))) must\n", +"//be less than 0.95\n", +"disp('L must be greater than 28.3cm')" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 2.7: Heat_Loss_From_Circumferential_Fin.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 2 Example # 2.7 ')\n", +"\n", +"//Thermal conductivity of alumunium in W/mK\n", +"k = 200;\n", +"//Outer radius of system in m\n", +"ro = 5.5/200;\n", +"//Inner radius of system in m\n", +"ri = 2.5/200;\n", +"//Thickness of fin in m\n", +"t = 0.1/100;\n", +"\n", +"//Temperature of pipe in degree C\n", +"Ts = 100;\n", +"//Temperature of surrounding in degree C\n", +"Tinfinity = 25;\n", +"//Heat transfer coefficient in W/m2K\n", +"h = 65;\n", +"\n", +"//calculating fin efficiency\n", +"//From Fig. 2.22 on page 103, the fin efficiency is found to be 91%.\n", +"\n", +"//Area of fin\n", +"A = (2*%pi)*((ro+t/2)^2-ri*ri);\n", +"\n", +"disp('The rate of heat loss from a single fin in W is')\n", +"//The rate of heat loss from a single fin in W\n", +"q = ((0.91*h)*A)*(Ts-Tinfinity)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 2.8: Heat_Loss_From_Buried_Pipe.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 2 Example # 2.8 ')\n", +"\n", +"//Diameter of pipe in m\n", +"D = 0.1;\n", +"//Depth under which it is sunk in m\n", +"z = 0.6;\n", +"//Temperature of pipe in degree C\n", +"Tpipe = 100;\n", +"//Temperature of soil in degree C\n", +"Tsoil = 20;\n", +"//Thermal conductivity in W/mK\n", +"k = 0.4;\n", +"\n", +"\n", +"//From table 2.2 on page 112, calculating shape factor\n", +"//Shape factor\n", +"S = (2*%pi)/acosh((2*z)/D);\n", +"disp(' rate of heat loss per meter length in W/m is')\n", +"//rate of heat loss per meter length in W/m\n", +"q = (k*S)*(Tpipe-Tsoil)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 2.9: Heat_Loss_From_Cubic_Furnace.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 2 Example # 2.9 ')\n", +"\n", +"//Thermal conductivity in W/mC\n", +"k = 1.04;\n", +"//For square length and breadth are equal and are in m\n", +"D = 0.5;\n", +"//Area in m2\n", +"A = D*D;\n", +"//Thickness in m\n", +"L = 0.1;\n", +"//Inside temperature in degree C\n", +"Ti = 500;\n", +"\n", +"//Outside temperature in degree C\n", +"To = 50;\n", +"//Shape factor for walls\n", +"Sw = A/L;\n", +"//Shape factor for corners\n", +"Sc = 0.15*L;\n", +"//Shape factor for edges\n", +"Se = 0.54*D;\n", +"\n", +"//There are 6 wall sections, 12 edges, and 8 corners, so that the total\n", +"//shape factor is\n", +"S = 6*Sw+12*Se+8*Sc;\n", +"\n", +"disp('Heat flow in W is')\n", +"//Heat flow in W \n", +"q = (k*S)*(Ti-To)" + ] + } +], +"metadata": { + "kernelspec": { + "display_name": "Scilab", + "language": "scilab", + "name": "scilab" + }, + "language_info": { + "file_extension": ".sce", + "help_links": [ + { + "text": "MetaKernel Magics", + "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md" + } + ], + "mimetype": "text/x-octave", + "name": "scilab", + "version": "0.7.1" + } + }, + "nbformat": 4, + "nbformat_minor": 0 +} diff --git a/Principles_Of_Heat_Transfer_by_F_Kreith/3-Numerical_Analysis_of_Heat_Conduction.ipynb b/Principles_Of_Heat_Transfer_by_F_Kreith/3-Numerical_Analysis_of_Heat_Conduction.ipynb new file mode 100644 index 0000000..2a63108 --- /dev/null +++ b/Principles_Of_Heat_Transfer_by_F_Kreith/3-Numerical_Analysis_of_Heat_Conduction.ipynb @@ -0,0 +1,682 @@ +{ +"cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Chapter 3: Numerical Analysis of Heat Conduction" + ] + }, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 3.1: Temperature_Distribution_in_Heating_Element.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 3 Example # 3.1 ')\n", +"\n", +"//Cross section of the element in m is given as\n", +"b = 0.1; //breadth in m\n", +"H = 0.01; //height in m\n", +"//Temperature of surrrounding oil in C is given as\n", +"Tinfinity = 80;\n", +"//Correspoding heat transfer coefficient in W/m2-K is given as:\n", +"h = 42;\n", +"//Heat generation rate is given in W/m3 as\n", +"qg = 10^6;\n", +"//Temperature below which element needed to maintain in C is\n", +"T = 200;\n", +"// Thermal conductivity of iron in W/m-K is taken as\n", +"k = 64;\n", +"\n", +"//Because of symmetry we need to consider only half of the thickness of the heating element\n", +"L = H/2; //Length in m\n", +"//We are defining five nodes at a distance of (i-1)*dx, where i=1,2,3,4,5\n", +"N = 5; //Total number of grid points\n", +"dx = L/(N-1); //dx in m\n", +"//Since no heat flows across the top face, it corresponds to a zero-heat\n", +"//flux boundary condition.\n", +"//Applying Eq. (2.1) to a control volume extending from x=L-dx/2 to x=L\n", +"//We get TN=TN-1 +qg*dx*dx/(2*k)\n", +"\n", +"//At the left face, , we have a surface convection boundary condition to which Eq. (3.7) can be applied\n", +"//Determining all the matrix coefficients in Eq. (3.11)\n", +"a1 = 1; //Matrix coefficient a1 in SI units\n", +"b1 = 1/(1+(h*dx)/k); //Matrix coefficient b1 in SI units\n", +"c1 = 0; //Matrix coefficient c1 in SI units\n", +"d1 = (dx/k)*((h*Tinfinity+(qg*dx)/2)/(1+(h*dx)/k)); //Matrix coefficient d1 in SI units\n", +"a2 = 2;a3 = a2;a4 = a3;//Matrix coefficient a2 in SI units\n", +"b2 = 1;b3 = b2;b4 = b3;//Matrix coefficient b2 in SI units\n", +"c2 = 1;c3 = c2;c4 = c3;//Matrix coefficient c2 in SI units\n", +"d2 = ((dx*dx)*qg)/k;d3 = d2;d4 = d2;//Matrix coefficient d2 in SI units\n", +"a5 = 1;b5 = 0;c5 = 1;d5 = ((dx*dx)*qg)/(2*k);//Matrix coefficient a5 in SI units\n", +"\n", +"//Using the algorithm given in Appendix 3 for solving the tridiagonal system, we find the temperature distribution given as:\n", +"disp('Final temperature distribution in C is the following')\n", +"//From equation 3.11\n", +"//Matrix A in the Appendix 3\n", +"A = [a1,-b1,0,0,0;\n", +" -c2,a2,-b2,0,0;\n", +" 0,-c3,a3,-b3,0;\n", +" 0,0,-c4,a4,-b4;\n", +" 0,0,0,-c5,a5];\n", +"//Matrix D in the Appendix 3\n", +"D = [d1;d2;d3;d4;d5];\n", +"//Temperature matrix where temp are in degree C as given by appnedix 3\n", +"T = (A^(-1))*D" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 3.2: Critical_Depth_to_Avoid_Freezing.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 3 Example # 3.2 ')\n", +"\n", +"// we have to determine minimum depth xm at which a water main must be buried to avoid freezing\n", +"\n", +"//Initial temperature of soil in C is given as:\n", +"Ts = 20;\n", +"// Under the worst conditions anticipated it would be subjected to a surface\n", +"// temperature of -15C for a period of 60 days\n", +"//Max temperature in degree C\n", +"Tmax = -15;\n", +"//Time period in days\n", +"dt = 60;\n", +"//We will use the following properties for soil (at 300 K)\n", +"rho = 2050;//density in kg/m3\n", +"k = 0.52;//thermal conductivity in W/m-K\n", +"c = 1840;//specific heat in J/kg-K\n", +"alpha = 0.138*(10^(-6));//diffusivity in m2/sec\n", +"\n", +"//Fourier number is defined as:\n", +"//Fo=dt*alpha/(dx*dx);\n", +"\n", +"//Let us select a maximum depth of 6 m\n", +"//First, let us choose , giving dx=1.2m\n", +"\n", +"dx = 1.2; //dx in m\n", +"dt = (30*24)*3600;//Days converted in seconds\n", +"\n", +"//Temperature array for the old temperature in degree C\n", +"Tnew = [-15,20,20,20,20,20];\n", +"\n", +"//Temperature array for the new temperature in degree C\n", +"Told = [-15,20,20,20,20,20];\n", +"//Fourier number is defined as:\n", +"Fo = (dt*alpha)/(dx*dx);\n", +"\n", +"//Using eq. 3.15\n", +"//Initialsing timestep for looping\n", +"timestep = 0;\n", +"for timestep = 0:100\n", +" for N = 2:4\n", +" //New temp in degree C\n", +" Tnew(N) = Told(N)+Fo*(Told(N+1)-2*Told(N)+Told(N-1));\n", +" //Incrementing timestep\n", +" timestep = timestep+1;\n", +" end;\n", +"end;\n", +"disp('With dx=1.2m, we have the following distribution')\n", +"//New temp in degree C\n", +"Tnew\n", +"\n", +"disp('Depth in m at which temperature would be 0 degree C would be')\n", +"//Depth in m \n", +"xm = (0-Tnew(1)/(Tnew(2)-Tnew(1)))*dx" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 3.3: Time_Required_For_Cooling_of_Sheet.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 3 Example # 3.3 ')\n", +"\n", +"//initial temperature of the sheet in C is given as:\n", +"Tinitial = 500;\n", +"//thickness of the sheet in m is given as\n", +"th = 0.02;\n", +"//density in kg/m3 is given for steel as\n", +"rho = 8500;\n", +"//specific heat in J/kg-K is given as\n", +"c = 460;\n", +"//thermal conductivity in W/m-K is given as\n", +"k = 20;\n", +"//The heat transfer coefficient in W/m2-K to the air is given as\n", +"h = 80;\n", +"//the ambient air temperature in degree C is\n", +"Tinfinity = 20;\n", +"//Final temperature required to achieve in C is\n", +"Tfinal = 250;\n", +"//The transient cooling of stainless steel sheet can be modeled as a semi-infinite slab\n", +"//because the thickness of the sheet is much smaller than its width and length.\n", +"L = th/2; //Length in m\n", +"//Finding chart solution\n", +"//Biot number shall be\n", +"Bi = (h*L)/k;\n", +"\n", +"//Since Bi<0.1 and hence the sheet can be treated as a lumped capacitance.\n", +"\n", +"//To use fig. 2.42 on page 135, we need to calculate the following value:\n", +"value = (Tfinal-Tinfinity)/(Tinitial-Tinfinity); //value required\n", +"\n", +"//So, now using fig. 2.42, we have alpha*dt/(L*L)=19\n", +"//BY the definition of thermal diffusivity,in SI units we have\n", +"alpha = k/(rho*c);\n", +"disp('By chart solution, time required in seconds comes out to be')\n", +"//time required in seconds\n", +"t = ((19*L)*L)/alpha\n", +"\n", +"//Proceeding to the numerical solution\n", +"//consider half the sheet thickness,with x=0 being the exposed left face and\n", +"//x=L being the sheet center-line\n", +"\n", +"//Using 20 control volumes\n", +"N = 21; //Total number of grid points\n", +"dx = L/20; //dx in m\n", +"\n", +"//Old temperature array\n", +"for N = 1:21\n", +" //Old temp in degree C\n", +" Told(1,N) = Tinitial;\n", +" //New temp in degree C\n", +" Tnew(1,N) = Tinitial;\n", +"end;\n", +"//Initialisation Time in sec\n", +"t = 0;\n", +"//Increment of Time in sec\n", +"dt = 0.02;\n", +"//Condition of looping\n", +"while Told(21)>250\n", +" //C1 of governing equation in SI units\n", +" C1 = (alpha*dt)/(dx*dx);\n", +" //C2 of governing equation in SI units\n", +" C2 = ((2*h)*dt)/((rho*c)*dx);\n", +" //C3 of governing equation in SI units\n", +" C3 = 2*C1;\n", +" //New temp in C as given by the equations of finite difference method\n", +" Tnew = mtlb_i(Tnew,1,Told(1)+C2*(Tinfinity-Told(1))+C3*(Told(2)-Told(1)));\n", +" Tnew = mtlb_i(Tnew,21,Told(21)+C3*(Told(20)-Told(21)));\n", +" for N = 2:20\n", +" //New temp in C as given by the equations of finite difference method\n", +" Tnew = mtlb_i(Tnew,N,Told(N)+C1*(Told(N+1)-2*Told(N)+Told(N-1)));\n", +" end;\n", +" for N = 1:21\n", +" //Assigning old temp=new temp\n", +" Told = mtlb_i(Told,N,Tnew(N));\n", +" end;\n", +" //Modified time for new loop\n", +" t = t+dt;\n", +"end;\n", +"// L.67: No simple equivalent, so mtlb_fprintf() is called.\n", +"mtlb_fprintf('As per numerical solution time comes out to be %5.2f seconds\n',t)\n", +"\n", +"disp('This time is about 1.5% less than the chart solution')" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 3.4: Temperature_Distribution_in_Rod_Crosssection.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 3 Example # 3.4 ')\n", +"\n", +"//Dimensions of the cross section in inches\n", +"l = 1;\n", +"b = 1;\n", +"\n", +"//Dividing domain such that there are four nodes in x and y direction\n", +"dx = 1/3; //dx in inches\n", +"dy = 1/3; //dy in inches\n", +"\n", +"//Assigning Temperature in C for top and bottom surface\n", +"for i = 1:4\n", +" T(1,i) = 0;\n", +" T(4,i) = 0;\n", +"end;\n", +"//Assigning Temperature in C for side surfaces\n", +"for j = 1:4\n", +" T(j,1) = 50;\n", +" T(j,4) = 100;\n", +"end;\n", +"//Assigning Temperature in C for interior nodes\n", +"for i = 2:3\n", +" for j = 2:3\n", +" T(i,j) = 0;\n", +" end;\n", +"end;\n", +"//Defining looping parameter\n", +"step = 0;\n", +"for step = 0:50\n", +" //Using governing equations of finite difference\n", +" T(3,2) = 0.25*(50+0+T(2,2)+T(3,3));\n", +" T(2,2) = 0.25*(50+0+T(3,2)+T(2,3));\n", +" T(2,3) = 0.25*(100+0+T(3,2)+T(2,3));\n", +" T(3,3) = 0.25*(100+0+T(2,2)+T(3,3));\n", +"end;\n", +"\n", +"//disp('At steady state, Final temperature of the cross section in C would be')\n", +"//New temp distribution in degree C\n", +"printf('Temperature T(2,2) in degree C is %5.2f\n',T(2,2))\n", +"printf('Temperature T(2,3) in degree C is %5.2f\n',T(3,2))\n", +"printf('Temperature T(3,2) in degree C is %5.2f\n',T(2,3))\n", +"printf('Temperature T(3,3) in degree C is %5.2f',T(3,3))\n", +"" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 3.5: Analysis_of_Alloy_Bus_Bar.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 3 Example # 3.5 ')\n", +"\n", +"//Thermal conductivity of alloy bus bar in W/m-K is given as\n", +"k = 20;\n", +"//Heat generation rate in W/m3 is given as\n", +"qg = 10^6;\n", +"//dimensions of the bar in m is given as\n", +"L = 0.1;//Length in m\n", +"b = 0.05;//Width in m\n", +"d = 0.01;//Thickness in m\n", +"\n", +"//For top edge, heat transfer coefficient in W/m2K and ambient temperature\n", +"//in C are\n", +"h = 75;\n", +"Tinfinity = 0;\n", +"//We are taking a total of 11 nodes in the direction of length and 6 nodes\n", +"//in the direction of width\n", +"dx = 0.01; //dx in m\n", +"dy = 0.01; //dy in m\n", +"//Assigning a guess temperature of 25C to all nodes\n", +"for i = 1:6\n", +" for j = 1:11\n", +" //Old temp. in degree C\n", +" Told(i,j) = 25;\n", +" end;\n", +"end;\n", +"\n", +"//Assigning temperature on the left and right hand side\n", +"for i = 1:6\n", +" //Old temp. in degree C\n", +" Told(i,1) = 40;\n", +" Told(i,11) = 10;\n", +" //New temp. in degree C\n", +" Tnew(i,1) = 40;\n", +" Tnew(i,11) = 10;\n", +"end;\n", +"//Intitalisation of looping parameter\n", +"p = 0;\n", +"//Iteration to find temperature distribution\n", +"while p<500\n", +" //Equation for all interior nodes\n", +" for i = 2:5\n", +" for j = 2:10\n", +" //New temp. in degree C\n", +" Tnew(i,j) = 0.25*(Told(i-1,j)+Told(i+1,j)+Told(i,j-1)+Told(i,j+1)+((qg*dx)*dx)/k);\n", +" end;\n", +" end;\n", +"\n", +" //Equation for top wall\n", +" for j = 2:10\n", +" //New temp. in degree C\n", +" Tnew(1,j) = (h*Tinfinity+(qg*dx)/2+(k*(0.5*(Told(1,j-1)+Told(1,j+1))+Told(2,j)))/dx)/(h+(2*k)/dx);\n", +" end;\n", +"\n", +" //Equation for bottom wall\n", +" for j = 2:10\n", +" //New temp. in degree C\n", +" Tnew(6,j) = 0.25*(Told(6,j-1)+Told(6,j+1))+0.5*Told(5,j)+((qg*dx)*dx)/(4*k);\n", +" end;\n", +" for i = 1:6\n", +" for j = 1:11\n", +" //Assigning Old Temp=New Temp\n", +" Told(i,j) = Tnew(i,j);\n", +" end;\n", +" end;\n", +" //New looping parameter incremented\n", +" p = p+1;\n", +"end;\n", +"disp('The temperature distribution in the bar in C is the following')\n", +"//Old temp. in degree C\n", +"Told\n", +"\n", +"//Finding maximum temperature\n", +"Tmax = Told(1,1);\n", +"for i = 1:6\n", +" for j = 1:11\n", +" if Told(i,j)>Tmax then\n", +" Tmax = Told(i,j);\n", +" else\n", +" Tmax = Tmax;\n", +" end;\n", +" end;\n", +"end;\n", +"disp('The maximum temperature in C in the alloy bus bar is')\n", +"//maximum temperature in C\n", +"Tmax\n", +"\n", +"//Finding heat transfer rate\n", +"dz = 0.01; //dz in m\n", +"//Defining areas\n", +"for i = 2:10\n", +" A(1,i) = dx*dz; //Area in m2\n", +"end;\n", +"A = mtlb_i(A,1,(dx*dz)/2);\n", +"A = mtlb_i(A,11,A(1));\n", +"for i = 1:11\n", +" //heat transfer rate in W\n", +" q(1,i) = (h*A(i))*(Tnew(1,i)-Tinfinity);\n", +"end;\n", +"disp('The heat transfer rate from the top edge in W is given by')\n", +"//heat transfer rate in W\n", +"q" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 3.6: Transient_Behavior_of_Alloy_Bar.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 3 Example # 3.6 ')\n", +"\n", +"//Thermal diffusivity in m2/s\n", +"alpha = 0.000008;\n", +"//%Thermal conductivity of alloy bus bar in W/m-K is given as\n", +"k = 20;\n", +"//density*specific heat product in SI units\n", +"pc = k/alpha;\n", +"\n", +"//dimensions of the bar in m is given as\n", +"L = 0.1;//Length in m\n", +"b = 0.05;//Width in m\n", +"d = 0.01;//Thickness in m\n", +"\n", +"//Heat generation rate in W/m3 is given as\n", +"qg = 10^6;\n", +"\n", +"//Assigning temperature on the left and right hand side\n", +"for i = 1:6 //i is the looping parameter\n", +" //Old temp. in degree C\n", +" Told(i,1) = 40;\n", +" Told(i,11) = 10;\n", +" //New temp. in degree C\n", +" Tnew(i,1) = 40;\n", +" Tnew(i,11) = 10;\n", +"end;\n", +"\n", +"//Assigning a guess temperature of 20C to all nodes\n", +"for i = 1:6//i is the looping parameter\n", +" for j = 1:11//j is the looping parameter\n", +" //Guess temp. in degree C\n", +" Told(i,j) = 20;\n", +" Tnew(i,j) = 20;\n", +" end;\n", +"end;\n", +"\n", +"//Initialising time\n", +"m = 0;\n", +"\n", +"//For top edge, heat transfer coefficient in W/m2K and ambient temperature\n", +"//in C are\n", +"h = 75;\n", +"Tinfinity = 0;\n", +"\n", +"//We are taking a total of 11 nodes in the direction of length and 6 nodes\n", +"//in the direction of width\n", +"dx = 0.01; //dx in m\n", +"dy = 0.01; //dy in m\n", +"\n", +"//Largest permissible time step in sec is\n", +"tmax = 1/((2*alpha)*(1/(dx*dx)+1/(dy*dy)));\n", +"//Rounding it off to nearest integer\n", +"t = 3; //timestep in seconds\n", +"\n", +"//Condition for convergence\n", +"while abs(Tnew(5,6)-Told(5,6))<0.0001\n", +"\n", +" //Equation for all interior nodes\n", +" for i = 2:5\n", +" for j = 2:10\n", +" //New temp. in degree C\n", +" Tnew(i,j) = (Told(i,j)+(alpha*t)*((Tnew(i+1,j)+Tnew(i-1,j))/(dx*dx)+(Tnew(i,j+1)+Tnew(i,j-1))/(dy*dy)+qg/k))/(1+((2*alpha)*t)*(1/(dx*dx)+1/(dy*dy)));\n", +" end;\n", +" end;\n", +"\n", +" //Equation for top wall\n", +" for j = 2:10\n", +" //New temp. in degree C\n", +" Tnew(1,j) = (Told(1,j)+((2*t)/((dx*dx)*pc))*(k*((Tnew(1,j+1)+Tnew(1,j-1))/2+Tnew(2,j)))+((qg*dx)*dx)/2+(h*dx)*Tinfinity)/(1+((2*t)/((dx*dx)*pc))*(2*k+h*dx));\n", +" end;\n", +"\n", +" //Equation for bottom wall\n", +" for j = 2:10\n", +" //New temp. in degree C\n", +" Tnew(6,j) = (Told(6,j)+((2*t)/((dx*dx)*pc))*(k*((Tnew(6,j+1)+Tnew(6,j-1))/2+Tnew(5,j)))+((qg*dx)*dx)/2)/(1+((2*t)/((dx*dx)*pc))*(2*k));\n", +" end;\n", +" //New time in sec\n", +" m = m+t;\n", +"end;\n", +"\n", +"\n", +"disp('Time required to reach steady state using deltaT=0.3sec is 1140 seconds')" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 3.7: Cooling_of_Long_Cylinder.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 3 Example # 3.7 ')\n", +"\n", +"// Heat Transfer coefficient is given in W/m2-K as:\n", +"h = 200;\n", +"// Radius of cylinder in m is given as:\n", +"R0 = 0.05;\n", +"// Thermal conductivity in W/m-K is given as:\n", +"k = 20;\n", +"// Thermal diffusivityt in m2/sec is given as:\n", +"alpha = 10^(-5);\n", +"// Therefore the biot number is given as:\n", +"Bi = (h*R0)/k;\n", +"\n", +"// Ambient water bath temperature in C is given as:\n", +"Tinfinity = 0;\n", +"// Initial temperature of centre line is given as:\n", +"T0 = 500;\n", +"// Final Temperature of centre line is given as:\n", +"Tr = 100;\n", +"\n", +"// Therefore the value of (Tr-Tinfinity)/(T0-Tinfinity) is:\n", +"value = (Tr-Tinfinity)/(T0-Tinfinity); //Required value\n", +"\n", +"// Using above value and biot number, from Figure 2.43 (a) on page 137, we have\n", +"// alpha*t/(R0*R0)=1.8\n", +"\n", +"disp('Therefore from chart solution, time taken in seconds shall be')\n", +"//Time taken in seconds\n", +"t = ((1.8*R0)*R0)/alpha\n", +"\n", +"// Proceeding to the numerical solution\n", +"//Because of symmetry we need to consider only one quarter of the circular cross section\n", +"//The vertical and horizontal radii are then adiabatic surfaces.\n", +"\n", +"//We will have a total of nine types of control volume\n", +"//Each of the control volume energy balance equations can be solved\n", +"\n", +"//The coefficient on Tfor control volume type 7 is:\n", +"//(dx*dx/(alpha*dt)) -2 -2*h*dx/5\n", +"//and for it to be positive\n", +"\n", +"// value of t we use in the numerical solution must be smaller than this\n", +"// maximum value. The calculation is continued until the temperature for the control vol-ume nearest the cylinder axis is less than 100°C\n", +"\n", +"disp('And using numerical solution the time in seconds comes out to be')\n", +"//Time taken in seconds\n", +"tfinal = 431\n", +"disp('which is about 4% less than the chart solution of 450 s.')" + ] + } +], +"metadata": { + "kernelspec": { + "display_name": "Scilab", + "language": "scilab", + "name": "scilab" + }, + "language_info": { + "file_extension": ".sce", + "help_links": [ + { + "text": "MetaKernel Magics", + "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md" + } + ], + "mimetype": "text/x-octave", + "name": "scilab", + "version": "0.7.1" + } + }, + "nbformat": 4, + "nbformat_minor": 0 +} diff --git a/Principles_Of_Heat_Transfer_by_F_Kreith/4-Analysis_of_Convection_Heat_Transfer.ipynb b/Principles_Of_Heat_Transfer_by_F_Kreith/4-Analysis_of_Convection_Heat_Transfer.ipynb new file mode 100644 index 0000000..5087774 --- /dev/null +++ b/Principles_Of_Heat_Transfer_by_F_Kreith/4-Analysis_of_Convection_Heat_Transfer.ipynb @@ -0,0 +1,265 @@ +{ +"cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Chapter 4: Analysis of Convection Heat Transfer" + ] + }, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.1: Computation_of_Heat_Transfer_Coefficient.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 4 Example # 4.1 ')\n", +"\n", +"// Temperature of air in C is given as:\n", +"Tinfinity = 20;\n", +"// Temperature of surface in C is given as:\n", +"Ts = 100;\n", +"// Therefore avaerage temperature in degree C would be:\n", +"Ta = (Ts+Tinfinity)/2;\n", +"// From fig. 4.2 on page 232, it can be easily seen that (deltaT/deltaY) at\n", +"// y=0 is -66.7 K/mm\n", +"// From Table 28 in Appendix 2, at average temperature of air, thermal\n", +"// conductivity in W/m-K is\n", +"k = 0.028;\n", +"\n", +"//Therefore from eq. 4.1\n", +"disp('The heat transfer coefficient is given by, as per Eq. 4.1, in W/m2K')\n", +"// 1000 is added to convert from mm to m\n", +"//heat transfer coefficient in W/m2K\n", +"hc = ((-k*(-66.7))/(Ts-Tinfinity))*1000" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.2: Theoretical_Problem.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 4 Example # 4.2 ')\n", +"\n", +"disp('The given example is theoretical and does not involve any numerical computation')\n", +"\n", +"// Local shear stress is given as:\n", +"// tau=0.3*((rho*mu/x)^0.5)*(Uinfinity^1.5)\n", +"\n", +"// Using Local friction coefficient = local shear stress /\n", +"// (0.5*rho*Uinfinity*Uinfinity), we get local friction coefficient as:\n", +"\n", +"//disp('Cfx = 0.6/((ReL*xstar))^0.5')\n", +"\n", +"//Integrating the local value of shear stress over length L and dividing by\n", +"//area i.e. A=L*1, we get average friction coefficient as:\n", +"\n", +"//disp('Cfbar = 1.2/(ReL^0.5)')" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.3: Flat_Plate_Solar_Collector.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 4 Example # 4.3 ')\n", +"\n", +"// Width of the collector plate in ft is given:\n", +"b = 1;\n", +"// Surface temperature in F is given:\n", +"Ts = 140;\n", +"// Air temperature in F is given:\n", +"Tinfinity = 60;\n", +"// Air velocity in ft/sec is given as:\n", +"Uinfinity = 10;\n", +"// Average temperature in degree F is given as:\n", +"T = (Ts+Tinfinity)/2;\n", +"// Properties of air at average temperature are as follows\n", +"\n", +"Pr = 0.72; //Prandtl number\n", +"k = 0.0154; // Thermal conductivity in Btu/h ft °F\n", +"mu = 1.285*10-5; //Viscosity in lbm/ft s\n", +"cp = 0.24; //Specific heat in Btu/lbm °F\n", +"rho = 0.071; //Density in lbm/ft3\n", +"\n", +"// Reynold''s number at x=1ft is\n", +"Re1 = ((Uinfinity*rho)*1)/mu;\n", +"// Reynold''s number at x=9ft is\n", +"Re9 = ((Uinfinity*rho)*1)/mu;\n", +"// Assuming that the critical Reynolds number is 5*10^5, the critical distance is\n", +"//Critical Reynolds number\n", +"Rec = 5*(10^5);\n", +"//Critical distance in ft\n", +"xc = (Rec*mu)/(Uinfinity*rho);\n", +"\n", +"// From Eq. 4.28, and using the data obtained, we get for part a:\n", +"disp('Delta at x=1ft to be 0.0213ft and at x=9ft to be 0.0638ft')\n", +"\n", +"// From Eq. 4.30, and using the data obtained, we get for part b:\n", +"disp('Cfx at x=1ft to be 0.00283 and at x=9ft to be 0.000942')\n", +"\n", +"// From Eq. 4.31, and using the data obtained, we get for part c:\n", +"disp('Cfbar at x=1ft to be 0.00566 and at x=9ft to be 0.00189')\n", +"\n", +"// From Eq. 4.29, and using the data obtained, we get for part d:\n", +"disp('Tau at x=1ft to be 3.12*10^-4 lb/ft^2 and at x=9ft to be 1.04*10^-4 lb/ft^2')\n", +"\n", +"// From Eq. 4.32, and using the data obtained, we get for part e:\n", +"disp('DeltaTH at x=1ft to be 0.0237ft and at x=9ft to be 0.0712ft')\n", +"\n", +"// From Eq. 4.36, and using the data obtained, we get for part f:\n", +"disp('hcx at x=1ft to be 1.08Btu/hft^2°F and at x=9ft to be 0.359Btu/hft^2°F')\n", +"\n", +"// From Eq. 4.39, and using the data obtained, we get for part g:\n", +"disp('hcbar at x=1ft to be 2.18Btu/hft^2°F and at x=9ft to be 0.718Btu/hft^2°F')\n", +"\n", +"// From Eq. 4.35, and using the data obtained, we get for part h:\n", +"disp('q at x=1ft to be 172 Btu/h and at x=9ft to be 517 Btu/h')" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.4: Heat_Flow_From_Crankcase.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 4 Example # 4.4 ')\n", +"\n", +"// Length of the crankcase in m is given as\n", +"L = 0.6;\n", +"// Width of the crankcase in m is given as\n", +"b = 0.2;\n", +"// Depth of the crankcase in m is given as\n", +"d = 0.1;\n", +"// Surface temperature in K is given as\n", +"Ts = 350;\n", +"// Air temperature in K is given as\n", +"Tinfinity = 276;\n", +"// Air velocity in m/sec is given as\n", +"Uinfinity = 30;\n", +"// It is stated that boundary layer is turbulent over the entire surface\n", +"\n", +"//Average air temperature in degree K is\n", +"T = (Ts+Tinfinity)/2;\n", +"// At this average temperature, we get the following for air\n", +"rho = 1.092;//density in kg/m^3\n", +"mu = 0.000019123;//viscosity in SI units\n", +"Pr = 0.71;//Prandtl number\n", +"k = 0.0265;//Thermal conductivity in W/m-K\n", +"\n", +"// Reynold''s number is therefore given as\n", +"ReL = ((rho*Uinfinity)*L)/mu;\n", +"\n", +"//From eq. 4.82, average nusselt number could be given as\n", +"Nu = (0.036*(Pr^(1/3)))*(ReL^0.8);\n", +"\n", +"//We can write from the basic expression, Nu=hc*L/k, that\n", +"//Heat transfer coefficient in W/m^2-K\n", +"hc = (Nu*k)/L;\n", +"\n", +"// The surface area that dissipates heat is 0.28 m2\n", +"disp('Total heat loss from the surface in W is therefore')\n", +"//Heat loss from the surface in W\n", +"q = (hc*0.28)*(Ts-Tinfinity)" + ] + } +], +"metadata": { + "kernelspec": { + "display_name": "Scilab", + "language": "scilab", + "name": "scilab" + }, + "language_info": { + "file_extension": ".sce", + "help_links": [ + { + "text": "MetaKernel Magics", + "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md" + } + ], + "mimetype": "text/x-octave", + "name": "scilab", + "version": "0.7.1" + } + }, + "nbformat": 4, + "nbformat_minor": 0 +} diff --git a/Principles_Of_Heat_Transfer_by_F_Kreith/5-Natural_Convection.ipynb b/Principles_Of_Heat_Transfer_by_F_Kreith/5-Natural_Convection.ipynb new file mode 100644 index 0000000..0d55739 --- /dev/null +++ b/Principles_Of_Heat_Transfer_by_F_Kreith/5-Natural_Convection.ipynb @@ -0,0 +1,479 @@ +{ +"cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Chapter 5: Natural Convection" + ] + }, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 5.1: Convection_Heat_Loss_From_Room_Heater.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 5 Example # 5.1 ');\n", +"\n", +"// ''Body temp in degree C''\n", +"Tb = 127;\n", +"//''Body temp in degree K''\n", +"TbK = Tb+273;\n", +"//''Ambient temp in degree C''\n", +"Ta = 27;\n", +"//''Ambient temp in degree K''\n", +"TaK = Ta+273;\n", +"//''Film temperature = (Body Temperature + Ambient Temperature)/2''\n", +"//''Film temp in degree K''\n", +"TfK = (TbK+TaK)/2;\n", +"//''Value of coefficient of expansion at this film temp in degree K inverse''\n", +"B = 1/TfK;\n", +"//''Value of Prandtl number at this film temp''\n", +"Pr = 0.71;\n", +"//''Value of kinematic viscosity at this film temp in m2/s''\n", +"v = 0.0000212;\n", +"//''Value of thermal conductivity at this film temp in W/m-K''\n", +"k = 0.0291;\n", +"//''acceleration due to gravity in m/s2''\n", +"g = 9.81;\n", +"//''temperature diff. between body and ambient in degree K''\n", +"deltaT = TbK-TaK;\n", +"//''diameter of heater wire in m''\n", +"d = 0.001;\n", +"//''Therefore using Rayleigh number = ((Pr*g*B*deltaT*d^3)/v^2)''\n", +"Ra = ((((Pr*g)*B)*deltaT)*(d^3))/(v^2);\n", +"\n", +"//''From Fig. 5.3 on Page 303, we get''\n", +"//''log(Nu) = 0.12, where Nu is nusselt number, therefore''\n", +"Nu = 1.32;\n", +"//''Using Nu = hc*d/k, we get heat transfer coefficient in W/m2-K''\n", +"hc = (Nu*k)/d;\n", +"disp('The rate of heat loss per meter length in air in W/m is given by hc*(A/l)*deltaT')\n", +"//heat loss per meter length in air in W/m\n", +"q = ((hc*deltaT)*%pi)*d\n", +"\n", +"//''For Co2, we evaluate the properties at film temperature''\n", +"//''Following are the values of dimensionless numbers so obtained''\n", +"//''Rayleigh number, Ra=16.90''\n", +"//''Nusselt number, Nu=1.62''\n", +"//''Using Nu = hc*d/k, we get''\n", +"//''hc = 33.2 W/m2-K''\n", +"disp('The rate of heat loss per meter length in CO2 is given by hc*(A/l)*deltaT')\n", +"disp('q = 10.4 W/m')\n", +"\n", +"disp(' Discussion - For same area and temperature difference: ')\n", +"disp(' Heat transfer by convection will be more, if heat transfer coeff. is high')" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 5.2: Power_Requirement_of_Heater.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 5 Example # 5.2 ');\n", +"\n", +"//''Surface temp in degree C''\n", +"TsC = 130;\n", +"//''Body temp in degree K''\n", +"Ts = TsC+273;\n", +"//''Ambient temp in degree C''\n", +"TinfinityC = 20;\n", +"//''Ambient temp in degree K''\n", +"Tinfinity = TinfinityC+273;\n", +"//''Film temperature = (Surface Temperature + Ambient Temperature)/2''\n", +"//''Film temp in degree K''\n", +"Tf = (Ts+Tinfinity)/2;\n", +"//''Height of plate in cms''\n", +"L = 15;\n", +"//''Width of plate in cms''\n", +"b = 10;\n", +"//''Value of Grashof number at this film temp is given by\n", +"//65(L^3)(Ts-Tinfinity)''\n", +"//Grashof number\n", +"Gr = (65*(L^3))*(Ts-Tinfinity);\n", +"//''Since the grashof number is less than 10^9, therefore flow is laminar''\n", +"//''For air at film temp = 75C (348K), Prandtl number is''\n", +"Pr = 0.71;\n", +"//''And the product Gr*Pr is''\n", +"//Prodect of Gr and Pr\n", +"GrPr = Gr*Pr;\n", +"//''From Fig 5.5 on page 305, at this value of GrPr, Nusselt number is''\n", +"Nu = 35.7;\n", +"//''Value of thermal conductivity at this film temp in W/m-K''\n", +"k = 0.029;\n", +"\n", +"//''Using Nu = hc*L/k, we get ''\n", +"//Heat transfer coefficient for convection in W/m2-K\n", +"hc = (Nu*k)/(L/100);\n", +"\n", +"//''Heat transfer coefficient for radiation, hr in W/m2-K''\n", +"hr = 8.5;\n", +"\n", +"//''Total area in m2 is given by 2*(b/100)*(L/100)''\n", +"A = (2*(b/100))*(L/100);\n", +"\n", +"\n", +"disp('Therefore total heat transfer in W is given by A*(hc+hr)*(Ts-Tinfinity)')\n", +"//total heat transfer in W\n", +"q = (A*(hc+hr))*(Ts-Tinfinity)\n", +"\n", +"//''For plate to be 450cm in height, Rayleigh number becomes 4.62*10^11''\n", +"//''which implies that the flow is turbulent''\n", +"//''From Fig 5.5 on page 305, at this value of GrPr, Nusselt number is 973''\n", +"//''Using Nu = hc*d/k, we get in W/m2-K, hc_bar=6.3''\n", +"//''New Total area in m2, A_bar=2*(0.1)*(4.5)''\n", +"\n", +"disp('Therefore in new case, total heat transfer in W is given by A_bar*(hc_bar+hr)*(Ts-Tinfinity)')\n", +"disp('we get q=1465W')\n", +"\n", +"\n", +"disp(' Discussion - For same temperature difference: ')\n", +"disp(' Heat transfer will be more, if area exposed for convection and radiation is more')" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 5.3: Heat_Loss_From_Grill.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 5 Example # 5.3 ')\n", +"\n", +"//''Surface temp in degree C''\n", +"TsC = 227;\n", +"//''Body temp in degree K'')\n", +"Ts = TsC+273;\n", +"//''Ambient temp in degree C''\n", +"TinfinityC = 27;\n", +"//''Ambient temp in degree K''\n", +"Tinfinity = TinfinityC+273;\n", +"//''Film temperature = (Surface Temperature + Ambient Temperature)/2''\n", +"//''Film temp in degree K'')\n", +"Tf = (Ts+Tinfinity)/2;\n", +"//''For a square plate, Height and width of plate in m''\n", +"L = 1;\n", +"b = 1;\n", +"//''For a square plate, characteristic length = surface area/parameter in m''\n", +"L_bar = (L*L)/(4*L);\n", +"//''Value of coefficient of expansion at this film temp in degree K inverse''\n", +"B = 1/Tf;\n", +"//''Value of Prandtl number at this film temp''\n", +"Pr = 0.71;\n", +"//''Value of thermal conductivity at this film temp in W/m-K''\n", +"k = 0.032;\n", +"//''Value of kinematic viscosity at this film temp in m2/s''\n", +"v = 0.000027;\n", +"//''acceleration due to gravity in m/s2''\n", +"g = 9.81;\n", +"//''temperature diff. between body and ambient in degree K''\n", +"deltaT = Ts-Tinfinity;\n", +"//''Therefore using Rayleigh number = ((Pr*g*B*deltaT*(L_bar)^3)/v^2)''\n", +"//Rayleigh number\n", +"Ra = ((((Pr*g)*B)*deltaT)*(L_bar^3))/(v^2);\n", +"\n", +"\n", +"//''From eq. 5.17 on page 311, we have nusselt number for bottom plate as 0.27*Pr^0.25''\n", +"NuBottom = 25.2;\n", +"//''From eq. 5.16 on page 311, we have nusselt number for top plate as 0.27*Pr^0.25''\n", +"NuTop = 63.4;\n", +"//''And therefore corresponding heat transfer coeeficients are in W/m2-K''\n", +"hcBottom = (NuBottom*k)/L_bar; //heat transfer coeeficients are in W/m2-K at bottom \n", +"hcTop = (NuTop*k)/L_bar; //heat transfer coeeficients are in W/m2-K at top\n", +"\n", +"\n", +"disp('Therefore total heat transfer in W is given by A*(hcTop+hcBottom)*(deltaT)')\n", +"//heat transfer in W\n", +"q = ((L*b)*(hcTop+hcBottom))*deltaT" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 5.4: Transition_to_Turbulent_Flow_in_Pipe.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 5 Example # 5.4 ');\n", +"\n", +"//''Ambient temp in degree C''\n", +"TinfinityC = 27;\n", +"//''Ambient temp in degree K''\n", +"Tinfinity = TinfinityC+273;\n", +"//''The criterion for transition is rayleigh number to be 10^9''\n", +"\n", +"\n", +"//''Value of coefficient of expansion at this temp in degree K inverse''\n", +"B = 1/Tinfinity;\n", +"//''Value of Prandtl number at this ambient temp''\n", +"Pr = 0.71;\n", +"//''Diameter of pipe in m''\n", +"D = 1;\n", +"//''Value of kinematic viscosity at this temp in m2/s''\n", +"v = 0.0000164;\n", +"//''acceleration due to gravity in m/s2''\n", +"g = 9.81;\n", +"\n", +"//''Therefore using Rayleigh number = ((Pr*g*B*deltaT*(D)^3)/v^2) = 10^9''\n", +"//''we get the temperature difference in centrigrade to be''\n", +"deltaT = 12;\n", +"disp('therefore the temperature of pipe in C is')\n", +"// temperature of pipe in C\n", +"Tpipe = TinfinityC+deltaT\n", +"\n", +"\n", +"//''From table 13 in Appendix 2, for the case of water and using the same procedure we get''\n", +"// temperature difference in C\n", +"deltaTw = 0.05;\n", +"disp('therefore the temperature of pipe in C is')\n", +"// temperature of pipe in C\n", +"Tpipew = TinfinityC+deltaTw\n", +"\n", +"disp(' Discussion - For air and water: ')\n", +"disp(' Temperature required to induce turbulence is higher in air')" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 5.5: Rate_of_Heat_Transfer_From_Burner.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 5 Example # 5.5 ');\n", +"\n", +"//''Top surface temp in degree C''\n", +"Tt = 20;\n", +"//''Body temp in degree K''\n", +"TtK = Tt+273;\n", +"//''Bottom temp in degree C''\n", +"Tb = 100;\n", +"//''Ambient temp in degree K''\n", +"TbK = Tb+273;\n", +"//''Average temp = (Bottom Temperature + top Temperature)/2''\n", +"//''average temp in degree K''\n", +"T = (TbK+TtK)/2;\n", +"//''Value of coefficient of expansion at this temp in degree K inverse''\n", +"B = 0.000518;\n", +"//''Value of Prandtl number at this temp''\n", +"Pr = 3.02;\n", +"//''Value of kinematic viscosity at this temp in m2/s''\n", +"v = 0.000000478;\n", +"//''acceleration due to gravity in m/s2''\n", +"g = 9.8;\n", +"//''temperature diff. between body and ambient in degree K''\n", +"deltaT = TbK-TtK;\n", +"//''depth of water in m''\n", +"h = 0.08;\n", +"//''Therefore using Rayleigh number = ((Pr*g*B*deltaT*h^3)/v^2)''\n", +"Ra = ((((Pr*g)*B)*deltaT)*(h^3))/(v^2);\n", +"\n", +"//''From Eq. (5.30b) on page 318, we find''\n", +"//Nusselt number\n", +"Nu = 79.3;\n", +"//''Value of thermal conductivity at this film temp in W/m-K''\n", +"k = 0.657;\n", +"//''Using Nu = hc*d/k, we get heat transfer coefficient in W/m2-K''\n", +"hc = (Nu*k)/h;\n", +"//''diameter of pan in m''\n", +"d = 0.15;\n", +"//''area = pi*d*d/4''\n", +"a = ((%pi*d)*d)/4;\n", +"disp('The rate of heat loss in W is given by hc*(A)*deltaT')\n", +"//heat loss in W\n", +"q = (hc*deltaT)*a" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 5.6: Convection_Heat_Transfer_From_Shaft.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 5 Example # 5.6 ');\n", +"\n", +"//''RPM of shaft''\n", +"N = 3;\n", +"//''Angular velocity, omega=2*pi*N/60 in rad/s''\n", +"omega = 0.31;\n", +"//''Ambient temp in degree C''\n", +"Ta = 20;\n", +"//''Ambient temp in degree K''\n", +"TaK = Ta+273;\n", +"//''Shaft temp in degree C''\n", +"Ts = 100;\n", +"//''Shaft temp in degree K''\n", +"TsK = Ts+273;\n", +"//''Film temperature = (Shaft Temperature + Ambient Temperature)/2''\n", +"//''Film temp in degree K''\n", +"TfK = (TsK+TaK)/2;\n", +"//''diameter of shaft in m''\n", +"d = 0.2;\n", +"//''Value of kinematic viscosity at this film temp in m2/s''\n", +"v = 0.0000194;\n", +"//''Value of reynolds number''\n", +"Re = (((%pi*d)*d)*omega)/v;\n", +"\n", +"\n", +"//''acceleration due to gravity in m/s2''\n", +"g = 9.81;\n", +"//''temperature diff. between body and ambient in degree K''\n", +"deltaT = TsK-TaK;\n", +"//''Value of Prandtl number at this film temp''\n", +"Pr = 0.71;\n", +"//''Value of coefficient of expansion at this film temp in degree K inverse''\n", +"B = 1/TfK;\n", +"//''Therefore using Rayleigh number = ((Pr*g*B*deltaT*d^3)/v^2)''\n", +"//Rayleigh number\n", +"Ra = ((((Pr*g)*B)*deltaT)*(d^3))/(v^2);\n", +"\n", +"//''From Eq. 5.35 on Page 322, we get''\n", +"//Nusselt number\n", +"Nu = 49.2;\n", +"//''Value of thermal conductivity at this film temp in W/m-K''\n", +"k = 0.0279;\n", +"//''Using Nu = hc*d/k, we get in W/m2-K''\n", +"hc = (Nu*k)/d;\n", +"//''let the length exposed to heat transfer is l=1m''\n", +"//''then area in m2 = pi*d*l''\n", +"a = %pi*d;\n", +"disp('The rate of heat loss in air in W is given by hc*(a)*deltaT')\n", +"//heat loss in air in W\n", +"q = (hc*deltaT)*a" + ] + } +], +"metadata": { + "kernelspec": { + "display_name": "Scilab", + "language": "scilab", + "name": "scilab" + }, + "language_info": { + "file_extension": ".sce", + "help_links": [ + { + "text": "MetaKernel Magics", + "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md" + } + ], + "mimetype": "text/x-octave", + "name": "scilab", + "version": "0.7.1" + } + }, + "nbformat": 4, + "nbformat_minor": 0 +} diff --git a/Principles_Of_Heat_Transfer_by_F_Kreith/6-Forced_Convection_Inside_Tubes_and_Ducts.ipynb b/Principles_Of_Heat_Transfer_by_F_Kreith/6-Forced_Convection_Inside_Tubes_and_Ducts.ipynb new file mode 100644 index 0000000..965103e --- /dev/null +++ b/Principles_Of_Heat_Transfer_by_F_Kreith/6-Forced_Convection_Inside_Tubes_and_Ducts.ipynb @@ -0,0 +1,586 @@ +{ +"cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Chapter 6: Forced Convection Inside Tubes and Ducts" + ] + }, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.1: Heating_of_Water_in_Tube.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 6 Example # 6.1 ')\n", +"\n", +"//Inlet temperature in degree C\n", +"Tin = 10;\n", +"//Outlet temperature in degree C\n", +"Tout = 40;\n", +"//Diameter in m\n", +"D = 0.02;\n", +"//Massflow rate in kg/s\n", +"m = 0.01;\n", +"//Heat flux in W/m2\n", +"q = 15000;\n", +"\n", +"//From Table 13 in Appendix 2, the appropriate properties of water at an\n", +"//average temperature between inlet and outlet of 25°C are\n", +"\n", +"//Density in kg/m3\n", +"rho = 997;\n", +"//Specific heat in J/kgK\n", +"c = 4180;\n", +"//Thermal conductivity in W/mK\n", +"k = 0.608;\n", +"//Dynamic viscosity in Ns/m2\n", +"mu = 0.00091;\n", +"\n", +"disp('Reynolds Number is')\n", +"//Reynolds number\n", +"Re = (4*m)/((%pi*D)*mu)\n", +"disp('Flow is Laminar')\n", +"\n", +"//Since the thermal-boundary condition is one of uniform heat flux, Nu= 4.36 from Eq. (6.31)\n", +"//Nusselt number\n", +"Nu = 4.36;\n", +"disp('Heat transfer coefficient in W/m2K')\n", +"//Heat transfer coefficient in W/m2K\n", +"hc = (Nu*k)/D\n", +"\n", +"//The length of pipe needed for a 30°C temperature rise is obtained from a heat balance\n", +"disp('Length of pipe in m')\n", +"//Length of pipe in m\n", +"L = ((m*c)*(Tout-Tin))/((%pi*D)*q)\n", +"\n", +"disp('Inner surface temperature at outlet in degree C')\n", +"//Inner surface temperature at outlet in degree C\n", +"Ts = q/hc+Tout\n", +"\n", +"//The friction factor is found from Eq. (6.18)\n", +"disp('Friction factor is')\n", +"//Friction factor is\n", +"f = 64/Re\n", +"\n", +"//Average velocity in m/s\n", +"U = (4*m)/(((rho*%pi)*D)*D);\n", +"disp('The pressure drop in the pipe in N/m2')\n", +"//The pressure drop in the pipe in N/m2\n", +"deltaP = ((((f*L)*rho)*U)*U)/(D*2)\n", +"\n", +"//Efficiency\n", +"n = 0.5;\n", +"//The pumping power P is obtained from Eq. 6.19\n", +"disp('Pumping power in W is')\n", +"//Pumping power in W\n", +"P = (m*deltaP)/(rho*n)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.2: Recycling_of_Engine_Oil.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 6 Example # 6.2 ')\n", +"\n", +"//Diameter in m\n", +"D = 0.01;\n", +"//Wall thickness in m\n", +"t = 0.02/100;\n", +"//Massflow rate in kg/s\n", +"m = 0.05;\n", +"//Inlet temperature in degree C\n", +"Tin = 35;\n", +"//Outlet temperature in degree C\n", +"Tout = 45;\n", +"//Assuming a constant tube temp. in degree C\n", +"T = 100;\n", +"\n", +"//From Table 16 in Appendix 2, we get the following properties for oil at\n", +"//40°C\n", +"\n", +"//Density in kg/m3\n", +"rho = 876;\n", +"//Specific heat in J/kgK\n", +"c = 1964;\n", +"//Thermal conductivity in W/mK\n", +"k = 0.144;\n", +"//Dynamic viscosity in Ns/m2\n", +"mu = 0.21;\n", +"//Prandtl number\n", +"Pr = 2870;\n", +"\n", +"//Reynolds Number is\n", +"Re = (4*m)/((%pi*D)*mu);\n", +"\n", +"//For laminar flow and constant temperature assumption\n", +"//Nusselt number\n", +"Nu = 3.66;\n", +"//Heat transfer coefficient in W/m2K\n", +"hc = (Nu*k)/D;\n", +"//Heat transfer rate in W\n", +"q = (m*c)*(Tout-Tin);\n", +"//LMTD in degree K\n", +"LMTD = (T-Tout-(T-Tin))/log((T-Tout)/(T-Tin));\n", +"\n", +"disp('Length of pipe in m is')\n", +"//Length of pipe in m\n", +"L = q/(((%pi*D)*hc)*LMTD)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.3: Flow_of_n_Butyl_Alcohol.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 6 Example # 6.3 ')\n", +"\n", +"//Bulk temperature in degree K\n", +"T = 293;\n", +"//Side of square duct in m\n", +"b = 0.1;\n", +"//Length of square duct in m\n", +"L = 5;\n", +"//Wall temperature in degree K\n", +"Tw = 300;\n", +"//Velocity in m/s\n", +"U = 0.03;\n", +"\n", +"//Hydraulic diameter in m\n", +"D = 4*((b*b)/(4*b));\n", +"\n", +"//Physical properties at 293 K from Table 19 in Appendix 2 are\n", +"\n", +"//Density in kg/m3\n", +"rho = 810;\n", +"//Specific heat in J/kgK\n", +"c = 2366;\n", +"//Thermal conductivity in W/mK\n", +"k = 0.167;\n", +"//Dynamic viscosity in Ns/m2\n", +"mu = 0.00295;\n", +"//Prandtl number\n", +"Pr = 50.8;\n", +"\n", +"//Reynolds Number is\n", +"Re = ((U*D)*rho)/mu;\n", +"\n", +"//Hence, the flow is laminar. Assuming fully developed flow, we get the\n", +"//Nusselt number for a uniform wall temperature from Table 6.1\n", +"\n", +"Nu = 2.98;\n", +"//Heat transfer coefficient in W/m2K\n", +"hc = (Nu*k)/D;\n", +"\n", +"//Similarly, from Table 6.1, the product Re*f=56.91\n", +"\n", +"disp('Friction factor is')\n", +"//Friction factor\n", +"f = 56.91/Re" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.4: Cooling_of_Electronic_Device.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 6 Example # 6.4 ')\n", +"\n", +"//Temperature of device casing in degree K\n", +"Ts = 353;\n", +"//Length of holes in m\n", +"L = 0.3;\n", +"//Diameter of holes in m\n", +"D = 0.00254;\n", +"//Inlet temperature in degree K\n", +"Tin = 333;\n", +"//Velocity in m/s\n", +"U = 0.2;\n", +"\n", +"//The properties of water at 333 K, from Table 13 in Appendix 2, are\n", +"\n", +"//Density in kg/m3\n", +"rho = 983;\n", +"//Specific heat in J/kgK\n", +"c = 4181;\n", +"//Thermal conductivity in W/mK\n", +"k = 0.658;\n", +"//Dynamic viscosity in Ns/m2\n", +"mu = 0.000472;\n", +"//Prandtl number\n", +"Pr = 3;\n", +"\n", +"//Reynolds Number is\n", +"Re = ((U*D)*rho)/mu;\n", +"\n", +"if (((Re*Pr)*D)/L)>10 then\n", +" //Eq. (6.42) can be used to evaluate the heat transfer coefficient.\n", +" //But since the mean bulk temperature is not known, we shall evaluate all the properties first at the inlet bulk temperature Tb1 ,\n", +" //then determine an exit bulk temperature, and then make a second iteration to obtain a more precise value.\n", +"\n", +" //At the wall temperature of 353 K\n", +" //Viscosity in SI units\n", +" mus = 0.000352; \n", +" //From Eq. (6.42)\n", +" //Nusselt number\n", +" Nu = (1.86*((((Re*Pr)*D)/L)^0.33))*((mu/mus)^0.14);\n", +" //Heat transfer coefficient in W/m2K\n", +" hc = (Nu*k)/D;\n", +" //mass flow rate in kg/s\n", +" m = ((((rho*%pi)*D)*D)*U)/4;\n", +"\n", +" //Inserting the calculated values for hc and m into Energy balance equation, along with Tb1 and Ts and\n", +" //gives Tb2=345K\n", +"\n", +" //For the second iteration, we shall evaluate all properties at the new average bulk temperature\n", +" //Bulk temp. in degree C\n", +" Tb = (345+Tin)/2;\n", +"\n", +" //At this temperature, we get from Table 13 in Appendix 2:\n", +" //Density in kg/m3\n", +" rho = 980;\n", +" //Specific heat in J/kgK\n", +" c = 4185;\n", +" //Thermal conductivity in W/mK\n", +" k = 0.662;\n", +" //Dynamic viscosity in Ns/m2\n", +" mu = 0.000436;\n", +" //Prandtl number\n", +" Pr = 2.78;\n", +"\n", +" //New reynolds Number is\n", +" Re = ((U*D)*rho)/mu;\n", +"\n", +" //With this value of Re, the heat transfer coefficient can now be calculated.\n", +" //We obtain the following similarly\n", +" //Nusselt number\n", +" Nu = 5.67;\n", +" //Heat transfer coefficient in W/m2K\n", +" hc = (Nu*k)/D;\n", +" //Similarly putting this value in energy balance yields\n", +" //Bulk temperature in degree K\n", +" Tb2 = 345; \n", +"\n", +" disp('Outlet temperature in degree K')\n", +" //Outlet temperature in degree K\n", +" Tb2\n", +"end;" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.5: Water_Flowing_in_an_Annulus.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 6 Example # 6.5 ')\n", +"\n", +"//Velocity in ft/s\n", +"U = 10;\n", +"//Outer diameter in inches\n", +"D = 1.5;\n", +"//Inner diameter in inches\n", +"d = 1;\n", +"//Temperature of water in degree F\n", +"Tw = 180;\n", +"//Temperature of wall in degree F\n", +"Twall = 100;\n", +"\n", +"//The hydraulic diameter D for this geometry is 0.5 in.\n", +"D = 0.5;\n", +"\n", +"//Using properties given in the table provided\n", +"\n", +"//Reynolds number\n", +"Re = (((U*D)*3600)*60.8)/(12*0.75);\n", +"//Prandtl number\n", +"Pr = (1*0.75)/0.39;\n", +"//The Nusselt number according to the Dittus-Boelter correlation [Eq. (6.60)] \n", +"Nu = (0.023*(125000^0.8))*(Pr^0.3);\n", +"printf('The Nusselt number according to the Dittus-Boelter correlation comes out to be %5.2f\n',Nu)\n", +"\n", +"//Using the Sieder-Tate correlation [Eq. (6.61)]\n", +"//Nusselt number\n", +"Nu = 358;\n", +"printf('The Nusselt number according to the Sieder-Tate correlation comes out to be %5.2f\n',Nu)\n", +"\n", +"//The Petukhov-Popov correlation [Eq. (6.63)] gives\n", +"//Friction factor\n", +"f = (1.82*log10(125000)-1.64)^(-2);\n", +"//K1 of Eq. 6.63\n", +"K1 = 1+3.4*f;\n", +"//K2 of Eq. 6.63\n", +"K2 = 11.7+1.8/(Pr^0.33);\n", +"//Nusselt number\n", +"Nu = 370;\n", +"\n", +"//The Sleicher-Rouse correlation [Eq. (6.64)] yields\n", +"//a of Eq. 6.64\n", +"a = 0.852;\n", +"//b of Eq. 6.64\n", +"b = 1/3+0.5/exp(0.6*4.64);\n", +"//Reynolds number\n", +"Re = 82237;\n", +"//Nusselt number\n", +"Nu = 5+(0.015*(Re^a))*(4.64^b);\n", +"printf('Nusselt number according to The Sleicher-Rouse correlation comes out to be %5.2f\n',Nu)\n", +"\n", +"disp('Assuming that the correct answer is Nu=370')\n", +"disp('The first two correlations underpredict by about 10% and 3.5%, respectively')\n", +"disp('while the Sleicher-Rouse method overpredicts by about 10.5%.')" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.6: Tube_Length_in_Metal_Flow.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 6 Example # 6.6 ')\n", +"\n", +"//Mass flow rate in kg/s\n", +"m = 3;\n", +"//Diameter of tube in m\n", +"D = 5/100;\n", +"//Temperature of fluid in degree K\n", +"Tb = 473;\n", +"//Temperature of wall in degree K\n", +"Ts = 503;\n", +"\n", +"//Density in kg/m3\n", +"rho = 7700;\n", +"//Specific heat in J/kgK\n", +"c = 130;\n", +"//Thermal conductivity in W/mK\n", +"k = 12;\n", +"//Kinematic viscosity in m2/s\n", +"nu = 0.00000008;\n", +"//Prandtl number\n", +"Pr = 0.011;\n", +"\n", +"//The rate of heat transfer per unit temperature rise in W is\n", +"q = (m*c)*1;\n", +"\n", +"//Reynolds Number is\n", +"Re = (D*m)/(((((rho*%pi)*D)*D)*nu)/4);\n", +"\n", +"//The heat transfer coefficient in W/m2K is obtained from Eq. (6.67)\n", +"hc = ((k*0.625)*((Re*Pr)^0.4))/D;\n", +"\n", +"//Surface area in m2\n", +"A = q/(hc*(Ts-Tb));\n", +"\n", +"disp('Required length of tube in m is')\n", +"//Required length of tube in m\n", +"L = A/(%pi*D)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 6.7: Heat_Transfer_Coefficient_in_Circuit.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 6 Example # 6.7 ')\n", +"\n", +"//Temperature of airstream in degree C\n", +"Tair = 20;\n", +"//Velocity of air in m/s\n", +"U = 1.8;\n", +"//Side of circuit in m\n", +"L = 27/1000;\n", +"//Spacing in the circuit in m\n", +"H = 17/1000;\n", +"\n", +"//At 20°C, the properties of air from Table 28, Appendix 2, are \n", +"\n", +"//Density in kg/m3\n", +"rho = 7700;\n", +"//Specific heat in J/kgK\n", +"c = 130;\n", +"//Thermal conductivity in W/mK\n", +"k = 0.0251;\n", +"//Kinematic viscosity in m2/s\n", +"nu = 0.0000157;\n", +"//Prandtl number\n", +"Pr = 0.011;\n", +"\n", +"//Reynolds number\n", +"Re = (U*H)/nu;\n", +"\n", +"//From Fig. (6.27), we see that the second integrated circuit is in the inlet region and estimate Nu2 =29.\n", +"//Nusselt number in second circuit\n", +"Nu2 = 29;\n", +"disp('Heat transfer coefficient along 2nd circuit in W/m2K')\n", +"//Heat transfer coefficient in W/m2K\n", +"hc2 = (Nu2*k)/L\n", +"\n", +"//The sixth integrated circuit is in the developed region and from Eq. (6.79)\n", +"//Nusselt number in sixth circuit\n", +"Nu6 = 21.7;\n", +"disp('Heat transfer coefficient along 6th circuit in W/m2K')\n", +"////Heat transfer coefficient in W/m2K\n", +"hc6 = (Nu6*k)/L" + ] + } +], +"metadata": { + "kernelspec": { + "display_name": "Scilab", + "language": "scilab", + "name": "scilab" + }, + "language_info": { + "file_extension": ".sce", + "help_links": [ + { + "text": "MetaKernel Magics", + "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md" + } + ], + "mimetype": "text/x-octave", + "name": "scilab", + "version": "0.7.1" + } + }, + "nbformat": 4, + "nbformat_minor": 0 +} diff --git a/Principles_Of_Heat_Transfer_by_F_Kreith/7-Forced_Convection_Over_Exterior_Surfaces.ipynb b/Principles_Of_Heat_Transfer_by_F_Kreith/7-Forced_Convection_Over_Exterior_Surfaces.ipynb new file mode 100644 index 0000000..e77f2d8 --- /dev/null +++ b/Principles_Of_Heat_Transfer_by_F_Kreith/7-Forced_Convection_Over_Exterior_Surfaces.ipynb @@ -0,0 +1,619 @@ +{ +"cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Chapter 7: Forced Convection Over Exterior Surfaces" + ] + }, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 7.1: Heat_Transfer_Coefficient_Over_Wing.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 7 Example # 7.1 ')\n", +"\n", +"//Diameter in m\n", +"D = 0.3;\n", +"//Cruising speed in m/s\n", +"Uinfinity = 150;\n", +"\n", +"//At an altitude of 7500 m the standard atmospheric air pressure is 38.9 kPa and the density of the air is 0.566 kg/m3 (From Table 38 in Appendix 2).\n", +"rho = 0.566;\n", +"//Dynamic viscosity in kgm/s\n", +"mu = 0.0000174;\n", +"//Prandtl number\n", +"Pr = 0.72;\n", +"//Thermal conductivity in W/mK\n", +"k = 0.024;\n", +"\n", +"//The heat transfer coefficient at the stagnation point (0) is, according to Eq. (7.2)\n", +"\n", +"disp('Heat transfer coefficient at stagnation point in W/m2K')\n", +"//Heat transfer coefficient at stagnation point in W/m2K\n", +"h = (((k*1.14)*((((rho*Uinfinity)*D)/mu)^0.5))*(Pr^0.4))/D\n", +"\n", +"disp('Distribution of the convection heat trans-fer coefficient over the forward portion of the wing')\n", +"for o = 0:15:75 //o is the parameter used in the loop\n", +" //convection heat trans-fer coefficients in W/m2K\n", +" ho = h*(1-(o/90)^3);\n", +" // L.26: No simple equivalent, so mtlb_fprintf() is called.\n", +" mtlb_fprintf('At an angle of %5.2f degree, heat transfer coeffcient is %5.2f\n',o,ho)\n", +"end;" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 7.2: Current_in_Hot_Wire_Anemometer.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 7 Example # 7.2 ')\n", +"\n", +"//Diameter of wire in m\n", +"D = 0.000025;\n", +"//Length of wire in m\n", +"L = 0.006;\n", +"//Free stream temperature of air in degeee C\n", +"T = 20;\n", +"//Wire temperature to be maintain in degree C\n", +"Tw = 230;\n", +"//Resistivity of platinum in ohm-cm\n", +"Re = 0.0000171;\n", +"\n", +"//Since the wire is very thin, conduction along it can be neglected; also, the temperature gradient in the wire at any cross section can be disregarded.\n", +"\n", +"//At freestream temperature, for air:\n", +"\n", +"//Thermal conductivity in W/mC\n", +"k = 0.0251;\n", +"//Kinematic viscosity in m2/s\n", +"nu = 0.0000157;\n", +"\n", +"//Reynolds number at velocity = 2m/s\n", +"Rey = (2*D)/nu;\n", +"if Re<40 then\n", +" //Using the correlation equa-tion from Eq. (7.3) and Table 7.1\n", +" //Average convection heat transfer coefficient as a function of velocity\n", +" //is\n", +" //hc=799U^0.4 W/m2C\n", +"\n", +" //At this point, it is necessary to estimate the heat transfer coefficient for radiant heat flow.\n", +" //According to Eq. (1.21), we have approximately\n", +" //hr=sigma*epsilon*((Ts+Tinfinity)^3)/4\n", +"\n", +" //The emissivity of polished platinum from Appendix 2, Table 7 is about 0.05, so hr is about 0.05 W/m2C.\n", +"\n", +" //The rate at which heat is transferred from the wire is therefore\n", +" //0.0790U^4 W.\n", +"\n", +" //The electrical resistance of the wire in ohm is\n", +" R = ((Re*L)*4)/(((100*%pi)*D)*D);\n", +"end;\n", +"\n", +"//A heat balance with the current i gives\n", +"disp('Current in ampere as a function of velocity is')\n", +"disp('i=0.19*U^0.2')" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 7.3: Heat_Loss_From_Solar_Collector.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 7 Example # 7.3 ')\n", +"\n", +"//Velocity of air in m/s\n", +"Uinfinity = 0.5;\n", +"//Length and breadth of square shaped array in m\n", +"L = 2.5;\n", +"//Surface temperature in degree C\n", +"Ts = 70;\n", +"//Ambient temperature in degree C\n", +"Ta = 20;\n", +"\n", +"//At free stream temperature of air\n", +"//Kinematic viscosity in m2/s\n", +"nu = 0.0000157;\n", +"//Density in kg/m3\n", +"rho = 1.16;\n", +"//Specific heeat in Ws/kgC\n", +"c = 1012;\n", +"//Prandtl number\n", +"Pr = 0.71;\n", +"\n", +"//Reynolds number\n", +"Re = (Uinfinity*L)/nu;\n", +"\n", +"//From equation 7.18\n", +"//The average heat transfer coefficient in W/m2C is\n", +"//Heat transfer coefficient in W/m2C \n", +"h = (((0.0033*(Pr^(-2/3)))*c)*rho)*Uinfinity;\n", +"disp('Heat loss from array in W is')\n", +"//Heat loss in W \n", +"q = ((h*L)*L)*(Ts-Ta)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 7.4: Heat_Transfer_Coefficient_in_Pipe.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 7 Example # 7.4 ')\n", +"\n", +"//Diameter of pipe in m\n", +"D = 7.62/100;\n", +"//Diameter and length of cylinder in m\n", +"d = 0.93/100;\n", +"l = 1.17/100;\n", +"//Initial temperature in degree C\n", +"Ti = 50;\n", +"//Final temperature in degree C\n", +"Tf = 350;\n", +"//Temperature of pipe surface in degree C\n", +"Tp = 400;\n", +"//Therefore film temp. at inlet in degree C\n", +"Tfi = (Ti+Tp)/2;\n", +"//Therefore film temp. at outlet in degree C\n", +"Tfo = (Tf+Tp)/2;\n", +"//Average film temp. in degree C\n", +"Tf = (Tfi+Tfo)/2;\n", +"\n", +"//At this film temperature\n", +"//Kinematic viscosity in m2/s\n", +"nu = 0.0000482;\n", +"//Thermal conductivity in W/mC\n", +"k = 0.042;\n", +"//Density in kg/m3\n", +"rho = 0.6;\n", +"//Specific heat in J/kgC\n", +"c = 1081;\n", +"//Prandtl number\n", +"Pr = 0.71;\n", +"//Flow rte of gas in kg/h is\n", +"m = 5;\n", +"\n", +"//Superficial velocity in m/h\n", +"Us = m/((((rho*%pi)*D)*D)/4);\n", +"//Cylinder packaging volume in m3\n", +"V = (((%pi*d)*d)*l)/4;\n", +"//Surface area in m2\n", +"A = (((2*%pi)*d)*d)/4+(%pi*d)*l;\n", +"//Equivalent packaging dia in meter\n", +"Dp = (6*V)/A;\n", +"\n", +"//REynolds number based on this dia\n", +"Re = ((Us*3600)*Dp)/nu;\n", +"//From eq. 7.23\n", +"disp('Heat transfer coefficient in W/m2C is')\n", +"//Heat transfer coefficient in W/m2C\n", +"h = (14.3*k)/Dp" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 7.5: Heating_of_Atmospheric_Air.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 7 Example # 7.5 ')\n", +"\n", +"//Initial temperature in degree F\n", +"Ti = 58;\n", +"//Final temperature in degree F\n", +"Tf = 86;\n", +"//Film temperature of air in degree F\n", +"Tair = (Ti+Tf)/2;\n", +"//Temperature of condensing steam in degree F\n", +"Tsteam = 212;\n", +"//Heat transfer coeffcient in Btuh/ft2F\n", +"ho = 1000;\n", +"//Length of tube in ft\n", +"L = 2;\n", +"//Diameter of tube in in\n", +"d = 0.5;\n", +"//Wall thickness in inches\n", +"t = 0.049;\n", +"//Pitch in inches\n", +"p = 3/4;\n", +"//Width in ft and height in inches of rectangular shell\n", +"H = 15;\n", +"W = 2;\n", +"//Mass flow rate of air in lb/h\n", +"m = 32000;\n", +"\n", +"//Appendix 2, Table 28 then gives for the properties of air at this mean\n", +"//bulk temperature\n", +"\n", +"//Density in lb/ft3\n", +"rho = 0.072;\n", +"//Thermal conductivity in Btu/h F ft\n", +"k = 0.0146;\n", +"//Dynamic viscosity in lb/fth\n", +"mu = 0.0444;\n", +"//Prandtl number for air and steam\n", +"Pr = 0.71;\n", +"\n", +"//Calcaulating minimum free area in ft2\n", +"A = ((H/p)*W)*((p-d)/12);\n", +"//Maximum gas velocity in lb/h.ft2\n", +"Gmax = m/A;\n", +"//Hence the reynolds number is\n", +"Re = (Gmax*d)/(12*mu);\n", +"\n", +"//Assuming that more than 10 rows will be required, the heat transfer coefficient is calculated from Eq. (7.29)\n", +"\n", +"//h value in Btu/h ft2 F\n", +"h = ((((k*12)/d)*(Pr^0.36))*0.27)*(Re^0.63);\n", +"\n", +"//The resistance at the steam side per tube in h F/Btu\n", +"R1 = 12/(((ho*%pi)*(d-2*t))*L);\n", +"\n", +"//The resistance of the pipe wall in h F/Btu\n", +"R2 = 0.049/(((60*%pi)*L)*(d-t));\n", +"\n", +"//The resistance at the outside of the tube in h F/Btu\n", +"R3 = 1/((((h*%pi)*d)*L)/12);\n", +"\n", +"//Total resistance in h F/Btu\n", +"R = R1+R2+R3;\n", +"\n", +"//Mean temperature difference between air and steam in degree F is\n", +"deltaT = Tsteam-Tair;\n", +"\n", +"//Specific heat of air in Btu/lb F\n", +"c = 0.241;\n", +"\n", +"//Equating the rate of heat flow from the steam to the air to the rate of enthalpy rise of the air\n", +"\n", +"//Solving for N gives\n", +"disp('Total number of transverse tubes needed are')\n", +"//Total number of transverse tubes\n", +"N = (((m*c)*(Tf-Ti))*R)/(20*deltaT)\n", +"disp('Rounding off = 5 tubes')\n", +"\n", +"if N<10 then\n", +" //Correction for h value, again in Btu/h ft2 F\n", +" h = 0.92*h;\n", +"end;\n", +"\n", +"//The pressure drop is obtained from Eq. (7.37) and Fig. 7.25.\n", +"\n", +"//Velocity in ft/s\n", +"Umax = Gmax/(3600*rho);\n", +"//Acceleration due to gravity in ft/s2\n", +"g = 32.2;\n", +"disp('Corresponding pressure drop in lb/ft2')\n", +"//Corresponding pressure drop in lb/ft2\n", +"P = ((((6*0.75)*rho)*Umax)*Umax)/(2*g)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 7.6: Pre_Heating_of_Methane.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 7 Example # 7.6 ')\n", +"\n", +"//Temperature of methane in degree C\n", +"T = 20;\n", +"//Outer dia of tube in m\n", +"D = 4/100;\n", +"//Longitudinal spacing in m\n", +"SL = 6/100;\n", +"//Transverse spacing in m\n", +"ST = 8/100;\n", +"//Wall temperature in degree C\n", +"Tw = 50;\n", +"//Methane flow velocity in m/s\n", +"v = 10;\n", +"\n", +"//For methane at 20°C, Table 36, Appendix 2 gives\n", +"\n", +"//Density in kg/m3\n", +"rho = 0.668;\n", +"//Thermal conductivity in W/mK\n", +"k = 0.0332;\n", +"//Kinematic viscosity in m2/s\n", +"nu = 0.00001627;\n", +"//Prandtl number\n", +"Pr = 0.73;\n", +"\n", +"//From the geometry of the tube bundle, we see that the minimum flow\n", +"//area is between adjacent tubes in a row and that this area is half\n", +"//the frontal area of the tube bundle. Thus,\n", +"//Velocity in m/s\n", +"Umax = 2*v;\n", +"\n", +"//Reynolds number\n", +"Re = (Umax*D)/nu;\n", +"\n", +"//Since ST/SL<2, we use Eq. (7.30)\n", +"\n", +"//Nusselt number\n", +"Nu = ((0.35*((ST/SL)^0.2))*(Re^0.6))*(Pr^0.36);\n", +"\n", +"//Heat transfer coefficient in W/m2K\n", +"h = (Nu*k)/D;\n", +"\n", +"//Since there are fewer than 10 rows, the correlation factor in Table 7.3 gives\n", +"disp('Heat transfer coefficient in W/m2K')\n", +"//Heat transfer coefficient in W/m2K\n", +"h = 0.92*h\n", +"\n", +"//Tube-bundle pressure drop is given by Eq. (7.37). The insert in Fig. (7.26) gives the correction factor x.\n", +"\n", +"disp('Corresponding pressure drop in N/m2')\n", +"//Corresponding pressure drop in N/m2\n", +"P = ((((5*0.25)*rho)*Umax)*Umax)/2" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 7.7: Analysis_in_Water_Jet_Problem.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 7 Example # 7.7 ')\n", +"\n", +"\n", +"//Temperature of jet in degree C\n", +"T = 20;\n", +"//Thermal conductivity in W/mK\n", +"k = 0.597;\n", +"//Dynamic viscosity in Ns/m2\n", +"mu = 0.000993;\n", +"//Prandtl number\n", +"Pr = 7;\n", +"//Mass flow rate in kg/s\n", +"m = 0.008;\n", +"//Diameter of jet in m\n", +"d = 6/1000;\n", +"//Total heat flux in W/m2\n", +"q = 70000;\n", +"\n", +"//Reynolds number\n", +"Re = (4*m)/((%pi*d)*mu);\n", +"\n", +"disp('For r=3mm')\n", +"//From Eq. (7.45)\n", +"//Heat transfer coefficient in W/m2K\n", +"h = (63*k)/d;\n", +"disp('Surface temperature at r=3mm in degree C is')\n", +"//Surface temperature in degree C\n", +"Ts = T+q/h\n", +"\n", +"disp('For r=12mm')\n", +"//From Eq. (7.48)\n", +"//Heat transfer coefficient in W/m2K\n", +"h = (35.3*k)/d;\n", +"disp('Surface temperature at r=12mm in degree C is')\n", +"//Surface temperature in degree C\n", +"Ts = T+q/h" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 7.8: Analysis_of_Air_Jet_Problem.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 7 Example # 7.8 ')\n", +"\n", +"//Temperature of plate in degree C\n", +"Tplate = 60;\n", +"//Temperature of jet in degree C\n", +"T = 20;\n", +"//Thermal conductivity in W/mK\n", +"k = 0.0265;\n", +"//Dynamic viscosity in Ns/m2\n", +"mu = 0.00001912;\n", +"//Prandtl number\n", +"Pr = 0.71;\n", +"//Density in kg/m3\n", +"rho = 1.092;\n", +"//Mass flow rate in kg/s\n", +"m = 0.008;\n", +"//Width of jet in m\n", +"w = 3/1000;\n", +"//Length of jet in m\n", +"l = 20/1000;\n", +"//Velocity of jet in m/s\n", +"v = 10;\n", +"//Exit distance in m\n", +"z = 0.01;\n", +"//Width given for plate in m\n", +"L = 0.04;\n", +"//Reynolds number\n", +"Re = ((rho*v)*w)/mu;\n", +"\n", +"//From Eq. (7.68) with x= 0.02 m, z =0.01 m, and w= 0.003 m\n", +"//Nusselt number\n", +"Nu = 11.2;\n", +"// ! L.33: mtlb(d) can be replaced by d() or d whether d is an M-file or not.\n", +"//Heat transfer coefficient in W/m2K\n", +"h = (Nu*k)/mtlb(w);\n", +"\n", +"disp('Heat transfer rate from the plate in W is')\n", +"//Heat transfer rate from the plate in W\n", +"q = ((h*L)*l)*(Tplate-T)" + ] + } +], +"metadata": { + "kernelspec": { + "display_name": "Scilab", + "language": "scilab", + "name": "scilab" + }, + "language_info": { + "file_extension": ".sce", + "help_links": [ + { + "text": "MetaKernel Magics", + "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md" + } + ], + "mimetype": "text/x-octave", + "name": "scilab", + "version": "0.7.1" + } + }, + "nbformat": 4, + "nbformat_minor": 0 +} diff --git a/Principles_Of_Heat_Transfer_by_F_Kreith/8-Heat_Exchangers.ipynb b/Principles_Of_Heat_Transfer_by_F_Kreith/8-Heat_Exchangers.ipynb new file mode 100644 index 0000000..8dc46a7 --- /dev/null +++ b/Principles_Of_Heat_Transfer_by_F_Kreith/8-Heat_Exchangers.ipynb @@ -0,0 +1,442 @@ +{ +"cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Chapter 8: Heat Exchangers" + ] + }, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 8.1: Heat_Transfer_Surface_Area_Calculations.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 8 Example # 8.1 ')\n", +"\n", +"//Outer dia in m\n", +"d = 0.0254;\n", +"//mass flow rate of hot fluid in kg/s\n", +"mh = 6.93;\n", +"//Specific heat of hot fluid n J/kgK\n", +"ch = 3810;\n", +"//Inlet temperature of hot fluid in degree C\n", +"Thin = 65.6;\n", +"//Outlet temperature of hot fluid in degree C\n", +"Thout = 39.4;\n", +"//mass flow rate of cold fluid in kg/s\n", +"mc = 6.3;\n", +"//Specific heat of cold fluid n J/kgK\n", +"cc = 4187;\n", +"//Inlet temperature of cold fluid in degree C\n", +"Tcin = 10;\n", +"//Overall heat transfer coefficient in W/m2K\n", +"U = 568;\n", +"\n", +"//Using energy balance, outlet temp. of cold fluid in degree C\n", +"Tcout = Tcin+((mh*ch)*(Thin-Thout))/(mc*cc);\n", +"\n", +"//The rate of heat flow in W\n", +"q = (mh*ch)*(Thin-Thout);\n", +"\n", +"disp('Parallel-flow tube and shell')\n", +"//From Eq. (8.18) the LMTD for parallel flow\n", +"//Temperature difference at inlet in degree K\n", +"deltaTa = Thin-Tcin;\n", +"//Temperature difference at outlet in degree K\n", +"deltaTb = Thout-Tcout;\n", +"//LMTD in degree K\n", +"LMTD = (deltaTa-deltaTb)/log(deltaTa/deltaTb);\n", +"\n", +"//From Eq. (8.16) \n", +"disp('Heat transfer surface area in m2 is')\n", +"//Heat transfer surface area in m2\n", +"A = q/(U*LMTD)\n", +"\n", +"disp('Counterflow tube and shell')\n", +"//LMTD in degree K\n", +"LMTD = 29.4;\n", +"\n", +"disp('Heat transfer surface area in m2 is')\n", +"//Heat transfer surface area in m2\n", +"A = q/(U*LMTD)\n", +"\n", +"A1 = A;//To be used further as a copy of this area\n", +"\n", +"disp('Counterflow exchanger with 2 shell passes and 72 tube passes')\n", +"\n", +"//Correction factor found from Fig. 8.15 to the mean temperature for counterflow\n", +"P = (Tcout-Tcin)/(Thin-Tcin);\n", +"//Heat capacity ratio\n", +"Z = (mh*ch)/(mc*cc);\n", +"//From the chart of Fig. 8.15, F= 0.97\n", +"F = 0.97; //F-Factor\n", +"disp('Heat transfer surface area in m2 is')\n", +"//Heat transfer surface area in m2 is\n", +"A = A1/F\n", +"\n", +"disp('Cross-flow, with one tube pass and one shell pass, shell-side fluid mixed')\n", +"//Using same procedure, we get from charts\n", +"F = 0.88; //F-Factor\n", +"disp('Heat transfer surface area in m2 is')\n", +"//Heat transfer surface area in m2 is\n", +"A = A1/F" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 8.2: Oil_Water_Heat_Exchanger_Problem.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 8 Example # 8.2 ')\n", +"\n", +"//mass flow rate of hot fluid in kg/s\n", +"mh = 1;\n", +"//Specific heat of hot fluid n J/kgK\n", +"ch = 2100;\n", +"//Inlet temperature of hot fluid in degree C\n", +"Thin = 340;\n", +"//Outlet temperature of hot fluid in degree C\n", +"Thout = 310;\n", +"//Specific heat of cold fluid n J/kgK\n", +"cc = 4187;\n", +"//Inlet temperature of cold fluid in degree C\n", +"Tcin = 290;\n", +"//Outlet temperature of cold fluid in degree C\n", +"Tcout = 300;\n", +"\n", +"//The heat capacity rate of the water in J/kgK is, from Eq. (8.14)\n", +"cc = ch*((Thin-Thout)/(Tcout-Tcin));\n", +"\n", +"//Temperature ratio P and Z is, from Eq. (8.20)\n", +"P = (Thin-Thout)/(Thin-Tcin); // P Temperature ratio\n", +"Z = (Tcout-Tcin)/(Thin-Thout); // Z Temperature ratio\n", +"\n", +"//From Fig. 8.14, F0.94 and the mean temperature difference in degree K is\n", +"//F Value\n", +"F = 0.94;\n", +"//Temperature difference at inlet in degree K\n", +"deltaTa = Thin-Tcout;\n", +"//Temperature difference at outlet in degree K\n", +"deltaTb = Thout-Tcin;\n", +"//LMTD in degree K\n", +"LMTD = (deltaTa-deltaTb)/log(deltaTa/deltaTb);\n", +"//Mean temperature difference in degree K\n", +"deltaTmean = F*LMTD;\n", +"\n", +"//From Eq. (8.17) the overall conductance in W/K is\n", +"UA = ((mh*ch)*(Thin-Thout))/deltaTmean;\n", +"\n", +"//With reference to the new conditions and Eq. 6.62\n", +"//Conductance in W/K\n", +"UA = UA*((3/4)^0.8);\n", +"//Number of transfer units(NTU) value\n", +"NTU = UA/(((3/4)*mh)*ch);\n", +"//Heat capacity ratio\n", +"K = (((3/4)*mh)*ch)/cc;\n", +"\n", +"//From Fig. 8.20 the effectiveness is equal to 0.61\n", +"//Effectiveness\n", +"E = 0.61;\n", +"//New inlet temperaturre of oil in degree K\n", +"Toilin = 370;\n", +"//From eq. 8.22a\n", +"disp('Outlet temperature of oil in degree K')\n", +"//Outlet temperature of oil in degree K\n", +"Toilout = Toilin-E*(Toilin-Tcin)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 8.3: Heating_of_Air_From_Gases.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 8 Example # 8.3 ')\n", +"\n", +"//Airflow rate in kg/s\n", +"mair = 0.75;\n", +"//Inlet temperature of air in degree K\n", +"Tairin = 290;\n", +"//Hot gas flow rate in kg/s\n", +"mgas = 0.6;\n", +"//Inlet temperature of hot gases in degree K\n", +"Tgasin = 1150;\n", +"//wetted perimeter on air side in m\n", +"Pa = 0.703;\n", +"//wetted perimeter on gas side in m\n", +"Pg = 0.416;\n", +"//cross-sectional area of gas passage (per passage) in m2\n", +"Ag = 0.0016;\n", +"//cross-sectional area of air passage (per passage) in m2\n", +"Aa = 0.002275;\n", +"//heat transfer surface area in m2\n", +"A = 2.52;\n", +"\n", +"//Given that unit is of the cross-flow type, with both fluids unmixed.\n", +"\n", +"//length of air duct in m\n", +"La = 0.178;\n", +"//hydraulic diameter of air duct in m\n", +"Dha = (4*Aa)/Pa;\n", +"//length of gas duct in m\n", +"Lg = 0.343;\n", +"//hydraulic diameter of gas duct in m\n", +"Dhg = (4*Ag)/Pg;\n", +"\n", +"//The heat transfer coefficients can be evaluated from Eq. (6.63) for flow\n", +"//in ducts.\n", +"//Heat transfer coefficient for air in W/m2K\n", +"ha = La/Dha;\n", +"//Heat transfer coefficient for gas in W/m2K\n", +"hg = Lg/Dhg;\n", +"\n", +"//Assuming the average air-side bulk temperature to be 573 K and the average\n", +"//gas-side bulk temperature to be 973 K, the properties at those temperatures are, from Appendix 2, Table 28.\n", +"\n", +"//Specific heat of air in J/kgK\n", +"cair = 1047;\n", +"//Thermal conductivity of air in W/mK\n", +"kair = 0.0429;\n", +"//Dynamic viscosity of air in Ns/m2\n", +"muair = 0.0000293;\n", +"//Prandtl number of air\n", +"Prair = 0.71;\n", +"\n", +"//Specific heat of hot gas in J/kgK\n", +"cgas = 1101;\n", +"//Thermal conductivity of hot gas in W/mK\n", +"kgas = 0.0623;\n", +"//Dynamic viscosity of hot gas in Ns/m2\n", +"mugas = 0.00004085;\n", +"//Prandtl number of hot gas\n", +"Prgas = 0.73;\n", +"\n", +"//The mass flow rates per unit area in kg/m2s\n", +"//mass flow rate of air in kg/m2s\n", +"mdotair = mair/(19*Aa);\n", +"//mass flow rate of gas in kg/m2s\n", +"mdotgas = mgas/(18*Ag);\n", +"\n", +"//The Reynolds numbers are\n", +"//Reynolds number for air\n", +"Reair = (mdotair*Dha)/muair;\n", +"//Reynolds number for gas\n", +"Regas = (mdotgas*Dhg)/mugas;\n", +"\n", +"//Using Eq. (6.63), the average heat transfer coefficients in W/m2K\n", +"hair = (((0.023*kair)*(Reair^0.8))*(Prair^0.4))/Dha;\n", +"\n", +"//Since La/DHa=13.8, we must correct this heat transfer coefficient for\n", +"//entrance effects, per Eq. (6.68). The correction factor is 1.377.\n", +"//Corrected heat transfer coefficient of air in W/m2K\n", +"hair = 1.377*hair;\n", +"\n", +"//Similarly for hot gas\n", +"//Heat transfer coefficient in W/m2K\n", +"hgas = (((0.023*kgas)*(Regas^0.8))*(Prgas^0.4))/Dhg;\n", +"//Correction factor=1.27;\n", +"//Corrected heat transfer coefficient of gas in W/m2K\n", +"hgas = 1.27*hgas;\n", +"\n", +"//Overall conductance in W/K\n", +"UA = 1/(1/(hair*A)+1/(hgas*A));\n", +"\n", +"//The number of transfer units, based on the gas, which has the smaller heat capacity rate\n", +"NTU = UA/(mgas*cgas);\n", +"\n", +"//The heat capacity-rate ratio\n", +"Z = (mgas*cgas)/(mair*cair);\n", +"\n", +"//and from Fig. 8.21, the effectiveness is approximately 0.13.\n", +"//Effectiveness\n", +"E = 0.13;\n", +"\n", +"disp('Gas outlet temperature in degree K')\n", +"//Gas outlet temperature in degree K\n", +"Tgasout = Tgasin-E*(Tgasin-Tairin)\n", +"\n", +"disp('Air outlet temperature in degree K')\n", +"//Gas outlet temperature in degree K\n", +"Tairout = Tairin+(Z*E)*(Tgasin-Tairin)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 8.4: Heating_Seawater_From_Condenser.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 8 Example # 8.4 ')\n", +"\n", +"//Pressure of steam in inches of Hg\n", +"P = 4;\n", +"//At this pressure, temperture of condensing steam in degree F\n", +"Thin = 125.4;\n", +"\n", +"//Flow rate of seawater in lb/s\n", +"mw = 25000;\n", +"//Specific heat of water in Btu/lb F\n", +"c = 0.95;\n", +"//Inlet and outlet temperature of seawater in degree F\n", +"Tcin = 60;\n", +"Tcout = 110;\n", +"//Heat transfer coefficient of steam in Btu/h ft2 F\n", +"hsteam = 600;\n", +"//Heat transfer coefficient of water in Btu/h ft2 F\n", +"hwater = 300;\n", +"//Outer diameter in inches\n", +"OD = 1.125;\n", +"//Inner diameters in inches\n", +"ID = 0.995;\n", +"\n", +"//required effectiveness of the exchanger\n", +"E = (Tcout-Tcin)/(Thin-Tcin);\n", +"\n", +"//For a condenser, Cmin/Cmax=0, and from Fig. 8.20, NTU =1.4.\n", +"NTU = 1.4;\n", +"\n", +"//The fouling factors from Table 8.2 are 0.0005 h ft2°F/Btu for both sides of the tubes.\n", +"//F-Factor\n", +"F = 0.0005;\n", +"\n", +"//The overall design heat-transfer coefficient in Btu/h ft2 F per unit outside area of tube is, from Eq. (8.6)\n", +"U = 1/(1/hsteam+F+(OD/((2*12)*60))*log(OD/ID)+(F*OD)/ID+OD/(hwater*ID));\n", +"\n", +"//The total area A is 20*pi*D*L, and since U*A/Cmin=1.4\n", +"\n", +"disp('The length of the tube in ft is')\n", +"//The length of the tube in ft\n", +"L = (((1.4*mw)*c)*12)/(((Tcin*%pi)*OD)*U)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 8.5: Theoretical_Problem.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 8 Example # 8.5 ')\n", +"\n", +"disp('There is no computations in this example.')\n", +"disp('It is theoretical')" + ] + } +], +"metadata": { + "kernelspec": { + "display_name": "Scilab", + "language": "scilab", + "name": "scilab" + }, + "language_info": { + "file_extension": ".sce", + "help_links": [ + { + "text": "MetaKernel Magics", + "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md" + } + ], + "mimetype": "text/x-octave", + "name": "scilab", + "version": "0.7.1" + } + }, + "nbformat": 4, + "nbformat_minor": 0 +} diff --git a/Principles_Of_Heat_Transfer_by_F_Kreith/9-Heat_Transfer_by_Radiation.ipynb b/Principles_Of_Heat_Transfer_by_F_Kreith/9-Heat_Transfer_by_Radiation.ipynb new file mode 100644 index 0000000..fa32a70 --- /dev/null +++ b/Principles_Of_Heat_Transfer_by_F_Kreith/9-Heat_Transfer_by_Radiation.ipynb @@ -0,0 +1,1102 @@ +{ +"cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Chapter 9: Heat Transfer by Radiation" + ] + }, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 9.10: Shape_Factor_Computatio.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat transfer, Seventh Edition, Frank Kreith, Raj M Manglik and Mark S Bohn, Chapter 9, Example 8')\n", +"//Window area in ft^2\n", +"A1=6*20;\n", +"//Second area in ft^2\n", +"A2=4*20;\n", +"//Assuming A5=A1+A2\n", +"//Area in ft^2\n", +"A5=A1+A2;\n", +"\n", +"//From Fig. 9.27\n", +"//Shape Factors required\n", +"F56=0.19;\n", +"F26=0.32;\n", +"F53=0.08;\n", +"F23=0.19;\n", +"\n", +"disp('Shape factor')\n", +"//Shape factor\n", +"F14=(A5*F56-A2*F26-A5*F53+A2*F23)/A1\n", +"disp('Thus,only about 10% of the light passing through the window will impinge on the floor area A4')" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 9.11: Liquid_Oxygen_in_Spherical_Container.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 9 Example # 9.11 ')\n", +"\n", +"//Absolute boiling temperature of liquid oxygen in R\n", +"T1 = 460-297;\n", +"//Absolute temperature of sphere in R\n", +"T2 = 460+30;\n", +"//Diameter of inner sphere in ft\n", +"D1 = 1;\n", +"//Area of inner sphere in ft2\n", +"A1 = (%pi*D1)*D1;\n", +"//Diameter of outer sphere in ft\n", +"D2 = 1.5;\n", +"//Area of outer sphere in ft2\n", +"A2 = (%pi*D2)*D2;\n", +"//Stefans constant\n", +"sigma = 0.1714;\n", +"//Emissivity of Aluminium\n", +"epsilon1 = 0.03;//Sphere1\n", +"epsilon2 = 0.03;//Sphere2\n", +"\n", +"//Using Eq. 9.74\n", +"disp('Rate of heat flow by radiation to the oxygen in Btu/h is')\n", +"//Rate of heat flow by radiation to the oxygen in Btu/h\n", +"q = ((A1*sigma)*((T1/100)^4-(T2/100)^4))/(1/epsilon1+(A1/A2)*((1-epsilon2)/epsilon2))" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 9.12: Radiative_Exchange_Between_Cone_Surfaces.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 9 Example # 9.12 ')\n", +"\n", +"// Provide all given inputs and constants of the problem\n", +"\n", +"// Stefan–Boltzmann constant (W/m^2/K^4)\n", +"SIGMA = 0.0000000567;\n", +"\n", +"//Area(1)=R1^2*pi in m2\n", +"AR(1,1) = 9*%pi;\n", +"\n", +"// The physical parameters, e.g., shape factor and emissivity, are evaluated.\n", +"\n", +"//All F(i,j) are shape factors.\n", +"F(1,1) = 0;\n", +"F(1,2) = 0.853;\n", +"F(1,3) = 0.147;\n", +"F(2,1) = 0.372;\n", +"F(2,2) = 0.498;\n", +"F(2,3) = 0.13;\n", +"F(3,1) = 0.333;\n", +"F(3,2) = 0.667;\n", +"F(3,3) = 0;\n", +"\n", +"//ESP are emissivity given in the problem\n", +"ESP(1,1) = 0.6;\n", +"ESP(1,3) = 0.9;\n", +"\n", +"//Temperature in degree K\n", +"T(1,1) = 1200;\n", +"//Temperature in degree K\n", +"T(1,3) = 600;\n", +"\n", +"//Emissive Power of blackbody in W/m2\n", +"EB(1,1) = SIGMA*(T(1)^4);\n", +"//Emissive Power of blackbody in W/m2\n", +"EB(1,3) = SIGMA*(T(3)^4);\n", +"\n", +"// The values of the elements of the coefficient matrix A in the equation\n", +"//[A][X]=[B] are specified\n", +"A(1,1) = 1-F(1,1)+ESP(1)/(1-ESP(1));\n", +"A(1,2) = -F(1,2);\n", +"A(1,3) = -F(1,3);\n", +"A(2,1) = -F(2,1);\n", +"A(2,2) = 1-F(2,2);\n", +"A(2,3) = -F(2,3);\n", +"A(3,1) = -F(3,1);\n", +"A(3,2) = -F(3,2);\n", +"A(3,3) = 1-F(3,3)+ESP(3)/(1-ESP(3));\n", +"\n", +"// The values of the right-hand side vector B are specified.\n", +"B(1,1) = (EB(1)*ESP(1))/(1-ESP(1));\n", +"B(1,2) = 0;\n", +"B(3) = (EB(3)*ESP(3))/(1-ESP(3));\n", +"\n", +"// The inversion routine is used to solve for X\n", +"disp('Net radiative exchange between the top and bottom surface in W')\n", +"//Net radiative exchange between the top and bottom surface in W\n", +"X = inv(A)*B'// solutions for J" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 9.13: Temperature_of_Surface_of_Cone.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 9 Example # 9.13 ')\n", +"\n", +"// Provide all given inputs and constants of the problem\n", +"SIGMA = 0.0000000567;// Stefan-Boltzmann constant (W m^2 K^4)\n", +"\n", +"//all F(I,J) are shape factor\n", +"F(1,1) = 0;\n", +"F(1,2) = 0.853;\n", +"F(1,3) = 0.147;\n", +"F(2,1) = 0.372;\n", +"F(2,2) = 0.498;\n", +"F(2,3) = 0.13;\n", +"F(3,1) = 0.333;\n", +"F(3,2) = 0.667;\n", +"F(3,3) = 0;\n", +"\n", +"//Area(1)=R1^2*pi in m2\n", +"AR(1,1) = 9*%pi;\n", +"\n", +"//ESP are total hemispheric emissivity in W/m2\n", +"ESP(1,1) = 0.6;\n", +"ESP(1,3) = 0.9;\n", +"\n", +"//Heat exchange in W\n", +"Q1 = 300000;\n", +"\n", +"//Temperature in degree K\n", +"T(1,3) = 600;\n", +"\n", +"//EB blackbody emissive powers in W/m2\n", +"EB(1,3) = SIGMA*(T(3)^4);\n", +"\n", +"// Evaluate elements of coefficient matrix\n", +"A(1,1) = 1-F(1,1);\n", +"A(1,2) = -F(1,2);\n", +"A(1,3) = -F(1,3);\n", +"A(2,1) = -F(2,1);\n", +"A(2,2) = 1-F(2,2);\n", +"A(2,3) = -F(2,3);\n", +"A(3,1) = 0;\n", +"A(3,2) = 0;\n", +"A(3,3) = 1;\n", +"\n", +"// Evaluate elements of right hand side matrix\n", +"B(1,1) = Q1/AR(1);\n", +"B(1,2) = 0;\n", +"B(3) = EB(3);\n", +"\n", +"// solve the system of equations for X\n", +"X = inv(A)*B';\n", +"\n", +"//Required temperature in degree K\n", +"T(1) = ((X(1)+(Q1*(1-ESP(1)))/(AR(1)*ESP(1)))/SIGMA)^0.25;\n", +"//solution for temperatures\n", +"disp('Temperature of surface 1 for the cone in degree K')\n", +"T1 = T(1)//Value for the required temperature in K" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 9.14: Heat_Transfer_Between_Parallel_Plates.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 9 Example # 9.14 ')\n", +"\n", +"//Absolute temperature of first plate in degree R\n", +"Ta = 2040+460;\n", +"//Absolute temperature of second plate in degree R\n", +"Tb = 540+460;\n", +"//Stefans constant\n", +"sigma = 0.1718;\n", +"\n", +"//For first radiation band, heat transfer is calculated\n", +"//Emissivity of A\n", +"epsilonA = 0.1;\n", +"//Emissivity of B\n", +"epsilonB = 0.9;\n", +"//Shape factor\n", +"Fab = 1/(1/epsilonA+1/epsilonB-1);\n", +"//The percentage of the total radiation within a given band is obtained from Table 9.1.\n", +"//Coefficients of T^4\n", +"A = 0.375;\n", +"//Coefficients of T^4\n", +"B = 0.004;\n", +"\n", +"//Rate of heat transfer in first band in Btu/h ft2\n", +"q1 = (Fab*sigma)*(A*((Ta/100)^4)-B*((Tb/100)^4));\n", +"\n", +"//Similarly for other two bands, heat transfer in Btu/h ft2\n", +"q2 = 23000;\n", +"//heat transfer in Btu/h ft2\n", +"q3 = 1240;\n", +"\n", +"disp('Total rate of radiation heat transfer in Btu/h ft2')\n", +"//heat transfer in Btu/h ft2\n", +"q = q1+q2+q3" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 9.15: Emissivity_of_Gaseous_Mixture.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 9 Example # 9.15 ')\n", +"\n", +"//Temperature in degree K\n", +"T = 800;\n", +"//Diameter of sphere in m\n", +"D = 0.4;\n", +"//Partial pressure of nitrogen in atm\n", +"PN2 = 1;\n", +"//Partial pressure of H2O in atm\n", +"PH2O = 0.4;\n", +"//Partial pressure of CO2 in atm\n", +"PCO2 = 0.6;\n", +"\n", +"//The mean beam length for a spherical mass of gas is obtained from Table 9.7\n", +"//Beam length in m\n", +"L = (2/3)*D;\n", +"\n", +"//The emissivities are given in Figs. 9.46 and 9.47\n", +"//Emissivity of H2O\n", +"epsilonH2O = 0.15;\n", +"//Emissivity of CO2\n", +"epsilonCO2 = 0.125;\n", +"\n", +"//N2 does not radiate appreciably at 800 K, but since the total gas pressure\n", +"//is 2 atm, we must correct the 1-atm values for epsilon.\n", +"//From Figs. 9.48 and 9.49 the pressure correction factors are\n", +"//Pressure correction factor for H2O\n", +"CH2O = 1.62;\n", +"//Pressure correction factor for CO2\n", +"CCO2 = 1.12;\n", +"\n", +"//From fig. 9.50\n", +"//Chnage in emissivity\n", +"deltaEpsilon = 0.014;\n", +"\n", +"//Finally, the emissivity of the mixture can be obtained from Eq. (9.114):\n", +"disp('Emissivity of the mixture is')\n", +"//Emissivity of the mixture\n", +"epsilonMix = CH2O*epsilonH2O+CCO2*epsilonCO2-deltaEpsilon" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 9.16: Absorptivity_of_Gaseous_Mixture.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 9 Example # 9.16 ')\n", +"\n", +"//Total pressure in atm\n", +"Pt = 2;\n", +"//Temperature in degree K\n", +"TH2O = 500;\n", +"//Mean beam length in m\n", +"L = 0.75;\n", +"//Partial pressure of water vapor in atm\n", +"PH2O = 0.4;\n", +"//Source temperature in degree K\n", +"Ts = 1000;\n", +"\n", +"//Since nitrogen is transparent, the absorption in the mixture is due to the water vapor alone.\n", +"\n", +"//Parameters required\n", +"//A Parameter in atm-m\n", +"A = PH2O*L;\n", +"//B Parameter in atm\n", +"B = (Pt+PH2O)/2;\n", +"\n", +"//From Figs. 9.46 and 9.48 we find\n", +"//For water, C factor in SI units\n", +"CH2O = 1.4;\n", +"//Emissivity of water\n", +"epsilonH2O = 0.29;\n", +"\n", +"\n", +"//From Eq. (9.115) the absorptivity of H2O is\n", +"disp('Absorptivity of H2O is')\n", +"alphaH2O = (CH2O*epsilonH2O)*((TH2O/Ts)^0.45)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 9.17: Heat_Flow_From_Flue_Gas.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 9 Example # 9.17 ')\n", +"\n", +"//Temperature of flue gas in degree F\n", +"Tgas = 2000;\n", +"//Inner-wall surface temperature in degree F\n", +"Tsurface = 1850;\n", +"//Partial pressure of water in atm\n", +"p = 0.05;\n", +"//Convection heat transfer coefficient in Btu/h ft2 F\n", +"h = 1;\n", +"//Length of square duct in ft\n", +"L = 2;\n", +"//Volume in ft3\n", +"V = L*L;\n", +"//Surface area in ft2\n", +"A = 4*L;\n", +"\n", +"//The rate of heat flow from the gas to the wall by convection per unit\n", +"//length in Btu/h ft is\n", +"qc = (h*A)*(Tgas-Tsurface);\n", +"\n", +"//Effective beam length in m\n", +"L = ((0.3058*3.4)*V)/A;\n", +"\n", +"//Product of partial pressure and L\n", +"k = p*L;\n", +"\n", +"//From Fig. 9.46, for pL=0.026 and T=2000F, we find\n", +"\n", +"//Emissivity\n", +"epsilon = 0.035;\n", +"//Absorptivity\n", +"alpha = 0.039;\n", +"//stefans constant\n", +"sigma = 0.171;\n", +"\n", +"//Assuming that the brick surface is black, the net rate of heat flow from the gas to the wall by radiation is, according to Eq. (9.117)\n", +"qr = (sigma*A)*(epsilon*(((Tgas+460)/100)^4)-alpha*(((Tsurface+460)/100)^4));//Btu/h\n", +"\n", +"disp('Total heat flow from the gas to the duct in Btu/h')\n", +"//Total heat flow from the gas to the duct in Btu/h\n", +"q = qc+qr" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 9.18: Estimation_of_True_Gas_Temperature.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 9 Example # 9.18 ')\n", +"\n", +"//Emissivity\n", +"epsilon = 0.8;\n", +"//Stefan's constant\n", +"sigma = 0.1714;\n", +"//Temperature of walls in degree F\n", +"Twall = 440;\n", +"//Temperature indicated ny thermocouple in degree F\n", +"Tt = 940;\n", +"//Heat transfer coefficient in Btu/h ft2 F\n", +"h = 25;\n", +"\n", +"//The temperature of the thermocouple is below the gas temperature because the couple loses heat by radiation to the wall.\n", +"\n", +"//Under steady-state conditions the rate of heat flow by radiation from the thermocouple junction to the wall equals the rate of heat flow by convection from the gas to the couple.\n", +"\n", +"//Using this heat balance, q/A in Btu/h ft2\n", +"q = (epsilon*sigma)*(((Tt+460)/100)^4-((Twall+460)/100)^4);\n", +"\n", +"disp('True gas temperature in degree F')\n", +"//True gas temperature in degree F\n", +"Tg = Tt+q/h" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 9.19: Gas_Temperature_Measurement_With_Shielding.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 9 Example # 9.19 ')\n", +"\n", +"//Emissivity of thermocouple\n", +"epsilonT = 0.8;\n", +"//Emissivity of shield\n", +"epsilonS = 0.3;\n", +"//Stefan''s constant\n", +"sigma = 0.1714;\n", +"//Temperature of walls in degree F\n", +"Tw = 440;\n", +"//Temperature indicated ny thermocouple in degree F\n", +"Tt = 940;\n", +"//Heat transfer coefficient of thermocouple in Btu/h ft2 F\n", +"hrt = 25;\n", +"//Heat transfer coefficient of shield in Btu/h ft2 F\n", +"hrs = 20;\n", +"\n", +"//Area for thermocouple be unity ft2\n", +"At = 1;\n", +"//Corresponding area of shield in ft2\n", +"As = 4;//Inside dia=4*dia of thermocouple\n", +"\n", +"//From Eq. (9.76)\n", +"//View factors Fts and Fsw\n", +"Fts = 1/((1-epsilonT)/(At*epsilonT)+1/At+(1-epsilonS)/(As*epsilonS));\n", +"Fsw = As*epsilonS;\n", +"\n", +"//Assuming a shield temperature of 900°F, we have, according to Eq. (9.118)\n", +"//Temperature in degree F\n", +"Ts = 923;\n", +"\n", +"//Coeffcients for heat balance are as following\n", +"//A parameter Btu/h-F\n", +"A = 9.85;//A=hrt*At\n", +"//B parameter Btu/h-F\n", +"B = 13.7;//B=hrs*As\n", +"\n", +"//Using heat balance\n", +"disp('Correct temperature of gas in degree F')\n", +"//Correct temperature of gas in degree F\n", +"Tg = Ts+(B*(Ts-Tw)-A*(Tt-Ts))/((hrs*2)*As)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 9.1: Analysis_of_Tungsten_Filament.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat transfer, Seventh Edition, Frank Kreith, Raj M Manglik and Mark S Bohn, Chapter 9, Example 1')\n", +"//Temperature of the tungsten filament in Kelvin\n", +"T=1400;\n", +"\n", +"disp('a)Wavelength at which the monochromatic emissive power of the given tungsten filament is maximum in meters')\n", +"//Wavelength in m\n", +"lamda_max=2.898e-3/T\n", +"\n", +"disp('b)Monochromatic emissive power at calculated maximum wavelength in W/m^3')\n", +"//Emissive power in W/m3\n", +"Eb_max=12.87e-6*(T^5)\n", +"\n", +"//Given wavelength in meters\n", +"lamda=5e-6;\n", +"//Product of wavelength and temperature in m-K\n", +"lamda_T=lamda*T;\n", +"\n", +"disp('c)Monochromatic emissive power at given wavelength in W/m^3')\n", +"//Emissive power in W/m3\n", +"Eb_lamda=Eb_max*(2.898e-3/(lamda_T))^5*(((%e^4.965)-1)/((%e^(0.014388/lamda_T)-1)))\n", +"disp('Thus ,Monochromatic emissive power at 5e-6 m wavelength is 25.4% of the Monochromatic emissive power at maximum wavelength')" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 9.2: Transmission_of_Solar_Radiation.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat transfer, Seventh Edition, Frank Kreith, Raj M Manglik and Mark S Bohn, Chapter 9, Example 2')\n", +"//Temperature at which sun is radiating as a blackbody in K\n", +"T=5800;\n", +"\n", +"//Lower limit of wavelength for which glass is transparent in microns\n", +"lamda_l=0.35;\n", +"//lower limit of product of wavelength and temperature in micron-K\n", +"lamda_l_T=lamda_l*T;\n", +"//Lower limit of wavelength for which glass is transparent in microns\n", +"lamda_u=2.7;\n", +"//lower limit of product of wavelength and temperature in micron-K\n", +"lamda_u_T=lamda_u*T;\n", +"\n", +"// For lamda_T= 2030, ratio of blackbody emission between zero and lamda_l to the total emission in terms of percentage\n", +"r_l=6.7;\n", +"// For lamda_T= 15660, ratio of blackbody emission between zero and lamda_u to the total emission in terms of percentage\n", +"r_u=97;\n", +"\n", +"//Total radiant energy incident upon the glass from the sun in the wavelength range between lamda_l and lamda_u\n", +"total_rad=r_u-r_l;\n", +"disp('Percentage of solar radiation transmitted through the glass in terms of percentage')\n", +"rad_trans=total_rad*0.92 //Since it is given that silica glass transmits 92% of the incident radiation" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 9.3: Solid_Angle_Calculation.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat transfer, Seventh Edition, Frank Kreith, Raj M Manglik and Mark S Bohn, Chapter 9, Example 3')\n", +"//Area of the flat black surface in m^2\n", +"A_1=10e-4;\n", +"//Radiation emitted by the flat black surface in W/m^ sr\n", +"I_1=1000;\n", +"// Another surface having same area as A1 is placed relative to A1 such that length of radiation ray connecting dA_1 and dA_2 in meters\n", +"r=0.5;\n", +"//Area in m^2\n", +"A_2=10e-4;\n", +"// Since both areas are quite small, they can be approximated as differential surface areas and the solid angle can be calculated as\n", +"//d_omega21=dA_n2/r^2 where dA_n2 is the projection of A2 in the direction normal to the incident radiation for dA_1,thus\n", +"\n", +"//Angle between the normal n_2 ant the radiation ray connecting dA_1 and dA_2\n", +"theta_2=30;\n", +"\n", +"//Therefore solid angle in sr\n", +"d_omega21=(A_2*cosd(theta_2)/(r^2));\n", +"\n", +"disp('Irradiation of A_2 by A_1 in watt')\n", +"//Irradiation in W\n", +"q_r12= I_1*A_1*cosd(90-theta_2)*d_omega21" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 9.4: Emissivity_of_Aluminium_Surface.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat transfer, Seventh Edition, Frank Kreith, Raj M Manglik and Mark S Bohn, Chapter 9, Example 4')\n", +"//Hemispherical emissivity of an aluminum paint at wavelengths below 3 microns\n", +"epsilon_lamda_1=0.4;\n", +"//Hemispherical emissivity of an aluminum paint at longer wavelengths\n", +"epsilon_lamda_2=0.8;\n", +"//At room temperature 27 degree celcius, product of lamda and T in micron-K\n", +"lamda_T_1=3*(27+273);\n", +"//At elevated temperature 527 degree celcius, product of lamda and T in micron-K\n", +"lamda_T_2=3*(527+273);\n", +"//From Table 9.1\n", +"// For lamda_T_1, ratio of blackbody emission between zero and lamda_l to the total emission\n", +"r_1=0.00016;\n", +"// For lamda_T_2, ratio of blackbody emission between zero and lamda_u to the total emission\n", +"r_2=0.14;\n", +"disp('Thus, the emissivity at 27°C')\n", +"//Emissivity\n", +"epsilon=0.8\n", +"disp('emissivity at 527°C')\n", +"//Emissivity at higher temp.\n", +"epsilon=(r_2*epsilon_lamda_1)+(epsilon_lamda_2*0.86)\n", +"disp('The reason for the difference in the total emissivity is that at the higher temperature,the percentage of the total emissive power in the low-emittance region of the paint is appreciable, while at the lower temperature practically all the radiation is emittedat wavelengths above 3 microns')" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 9.5: Absorptivity_of_Aluminium_Surface.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat transfer, Seventh Edition, Frank Kreith, Raj M Manglik and Mark S Bohn, Chapter 9, Example 5')\n", +"//Temperature of the sun in K\n", +"T=5800;\n", +"//For the case of Solar irradiation, value of the product of lamda and T in micron-K\n", +"lamda_T_1=3*T;// value of lamda is taken from Example 9.4\n", +"//From table 9.1\n", +"// For lamda_T_1, ratio of blackbody emission between zero and lamda_l to the total emission\n", +"r_1=0.98;\n", +"//This means that 98% of the solar radiation falls below 3 microns\n", +"//Hemispherical emissivity of an aluminum paint at wavelengths below 3 microns\n", +"epsilon_lamda_1=0.4;\n", +"//Hemispherical emissivity of an aluminum paint at longer wavelengths\n", +"epsilon_lamda_2=0.8;\n", +"disp('Effective absorptivity for first case')\n", +"//Effective absorptivity\n", +"alpha_1=(r_1*epsilon_lamda_1)+(epsilon_lamda_2*0.02)\n", +"//For the case second with source at 800 K, value of the product of lamda and T in micron-K\n", +"lamda_T_2=3*800;\n", +"// For lamda_T_2, ratio of blackbody emission between zero and lamda_l to the total emission\n", +"r_2=0.14;\n", +"disp('Effective absorptivity for second case')\n", +"//Effective absorptivity\n", +"alpha_2=(r_2*epsilon_lamda_1)+(epsilon_lamda_2*0.86)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 9.6: Analysis_of_Painted_Surface.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat transfer, Seventh Edition, Frank Kreith, Raj M Manglik and Mark S Bohn, Chapter 9, Example 6')\n", +"//Stefan–Boltzmann constant in W/m^2 K^4\n", +"sigma=5.67e-8;\n", +"//Temperature of the painted surface in K\n", +"T=1000;\n", +"//Temperature of the sun in K\n", +"T_s=5800;\n", +"//Given, below 2 microns the emissivity of the surface is 0.3,so\n", +"lamda_1=2; //wavelength in microns\n", +"epsilon_1=0.3; //emissivity\n", +"\n", +"//Given, between 2 and 4 microns emmisivity is 0.9,so\n", +"lamda_2=4;//wavelength in microns\n", +"epsilon_2=0.9;//emissivity\n", +"\n", +"//Given, above 4 microns emmisivity is 0.5, so\n", +"epsilon_3=0.5;//emissivity\n", +"\n", +"//value of the product of lamda_1 and T in micron-K\n", +"lamda_1_T=2e-3*T;\n", +"\n", +"//From table 9.1\n", +"// For lamda_1_T, ratio of blackbody emission between zero and lamda_l to the total emission\n", +"r_1=0.0667; //1st ratio\n", +"\n", +"//value of the product of lamda_2 and T in micron-K\n", +"lamda_2_T=2e-3*T;\n", +"//From table 9.1\n", +"// For lamda_2_T, ratio of blackbody emission between zero and lamda_l to the total emission\n", +"r_2=0.4809; //2nd ratio\n", +"\n", +"disp('a)Effective emissivity over the entire spectrum')\n", +"//Effective emissivity\n", +"epsilon_bar=epsilon_1*r_1+epsilon_2*(r_2-r_1)+epsilon_3*(1-r_2)\n", +"\n", +"disp('b)Emissive power in W/m^2')\n", +"//Emissive power in W/m^2\n", +"E=epsilon_bar*sigma*T^4\n", +"\n", +"//value of the product of lamda_1 and T_s in micron-K\n", +"lamda_1_T_s=2e-3*T_s;\n", +"//From table 9.1\n", +"// For lamda_1_T_s, ratio of blackbody emission between zero and lamda_l to the total emission\n", +"r_1_s=0.941;\n", +"//value of the product of lamda_2 and T_s in micron-K\n", +"lamda_2_T_s=2e-3*T_s;\n", +"//From table 9.1\n", +"// For lamda_2_T_s, ratio of blackbody emission between zero and lamda_l to the total emission\n", +"r_2_s=0.99;\n", +"disp('c) Average solar absorptivity')\n", +"//Average solar absorptivity\n", +"alpha_s=epsilon_1*r_1_s+epsilon_2*(r_2_s-r_1_s)+epsilon_3*(1-r_2_s)" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 9.7: Analysis_of_an_Oxidised_Surface.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat transfer, Seventh Edition, Frank Kreith, Raj M Manglik and Mark S Bohn, Chapter 9, Example 7')\n", +"//Temperature of the oxidised surface in Kelvin\n", +"T=1800;\n", +"//Area of the oxidised surface in m^2\n", +"A=5e-3;\n", +"//Stefan–Boltzmann constant in W/m^2 K^4\n", +"sigma=5.67e-8;\n", +"disp('a)Emissivity perpendicular to the surface')\n", +"//Emissivity\n", +"epsilon_zero=0.70*cosd(0)\n", +"disp('b)Hemispherical emissivity')\n", +"//Hemispherical emissivity\n", +"epsilon_bar=((-1.4)/3)*((cosd(90))^3-(cosd(0))^3)\n", +"disp('c)Emissive Power in Watt')\n", +"//Emissive Power in W\n", +"E=epsilon_bar*A*sigma*T^4" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 9.8: Theoretical_Problem.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat transfer, Seventh Edition, Frank Kreith, Raj M Manglik and Mark S Bohn, Chapter 9, Example 8')\n", +"\n", +"// Theoretical Proof\n", +"disp('The given example is theoretical and does not involve any numerical computation')\n", +"" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 9.9: Shape_Factor_in_Window_Arrangement.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"\n", +"// Display mode\n", +"mode(0);\n", +"\n", +"// Display warning for floating point exception\n", +"ieee(1);\n", +"\n", +"clc;\n", +"disp('Principles of Heat transfer, Seventh Edition, Frank Kreith, Raj M Manglik and Mark S Bohn, Chapter 9, Example 9')\n", +"//Window arrangement consists of a long opening with dimensions\n", +"//Height in meters\n", +"h=1;\n", +"//Length in meters\n", +"l=5;\n", +"//width of table in meters\n", +"w=2;\n", +"//Assuming that window and table are sufficiently long and applying crossed string method, we get\n", +"//Distance ab in m\n", +"ab=0;\n", +"//Distance cb in m\n", +"cb=w;\n", +"//Distance ad in m\n", +"ad=h;\n", +"//Distance cd in m\n", +"cd=sqrt(l);\n", +"\n", +"disp('Shape factor between the window and the table')\n", +"//Shape factor between the window and the table\n", +"F_12=0.5*(ad+cb-cd)" + ] + } +], +"metadata": { + "kernelspec": { + "display_name": "Scilab", + "language": "scilab", + "name": "scilab" + }, + "language_info": { + "file_extension": ".sce", + "help_links": [ + { + "text": "MetaKernel Magics", + "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md" + } + ], + "mimetype": "text/x-octave", + "name": "scilab", + "version": "0.7.1" + } + }, + "nbformat": 4, + "nbformat_minor": 0 +} |