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author | nice | 2014-09-15 12:50:58 +0530 |
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committer | nice | 2014-09-15 12:50:58 +0530 |
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diff --git a/Fundamentals_Of_Engineering_Heat_And_Mass_Transfer/ch8.ipynb b/Fundamentals_Of_Engineering_Heat_And_Mass_Transfer/ch8.ipynb new file mode 100755 index 00000000..532f0847 --- /dev/null +++ b/Fundamentals_Of_Engineering_Heat_And_Mass_Transfer/ch8.ipynb @@ -0,0 +1,790 @@ +{ + "metadata": { + "name": "", + "signature": "sha256:ca5009f0cb9dd781f90e694bd80e1f1d823182523e44edb65991cb3279963181" + }, + "nbformat": 3, + "nbformat_minor": 0, + "worksheets": [ + { + "cells": [ + { + "cell_type": "heading", + "level": 1, + "metadata": {}, + "source": [ + "Chapter 8 : Natural Convection" + ] + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.1 Page No : 340" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math \n", + "\n", + "# Variables\n", + "L = 0.3;\t\t\t#Length of the glass plate in m\n", + "Ta = 27;\t\t\t#Temperature of air in degree C\n", + "Ts = 77;\t\t\t#Surface temperature in degree C\n", + "v = 4;\t\t\t#Velocity of air in m/s\n", + "\n", + "# Calculations\n", + "Tf = (Ta+Ts)/2;\t\t\t#Film temperature in degree C\n", + "k = 0.02815;\t\t\t#Thermal conductivity in W/m.K\n", + "v1 = (18.41*10**-6);\t\t\t#Kinematic viscosity in m**2/s\n", + "Pr = 0.7;\t\t\t#Prantl number\n", + "b = (3.07*10**-3);\t\t\t#Coefficient of thermal expansion in 1./K\n", + "Gr = (9.81*b*(Ts-Ta)*L**3)/v1**2;\t\t\t#Grashof number\n", + "q = L*((3.93*(1./math.sqrt(Pr))*(0.952+Pr)**0.25*Gr**(-0.25)));\t\t\t#Boundary layer thickness at the trailing edge of the plate in free convection in m\n", + "Re = (v*L)/v1;\t\t\t#Reynolds number\n", + "q1 = (5*L)/math.sqrt(Re);\t\t\t#Boundary layer thickness at the trailing edge of the plate in forced convection in m\n", + "\n", + "# Results\n", + "print 'Boundary layer thickness at the trailing edge of the plate in free convection is % 3.4f m \\\n", + "\\nBoundary layer thickness at the trailing edge of the plate in forced convection is %3.4f m'%(q,q1) \n", + "\n", + "\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Boundary layer thickness at the trailing edge of the plate in free convection is 0.0153 m \n", + "Boundary layer thickness at the trailing edge of the plate in forced convection is 0.0059 m\n" + ] + } + ], + "prompt_number": 2 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.2 Page No : 341" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math\n", + "# Variables\n", + "L = 0.3;\t\t\t#Length of the glass plate in m\n", + "Ta = 27;\t\t\t#Temperature of air in degree C\n", + "Ts = 77;\t\t\t#Surface temperature in degree C\n", + "v = 4;\t\t\t#Velocity of air in m/s\n", + "\n", + "# Calculations\n", + "Tf = (Ta+Ts)/2;\t\t\t#Film temperature in degree C\n", + "k = 0.02815;\t\t\t#Thermal conductivity in W/m.K\n", + "v1 = (18.41*10**-6);\t\t\t#Kinematic viscosity in m**2/s\n", + "Pr = 0.7;\t\t\t#Prantl number\n", + "b = (3.07*10**-3);\t\t\t#Coefficient of thermal expansion in 1./K\n", + "Gr = (9.81*b*(Ts-Ta)*L**3)/v1**2;\t\t\t#Grashof number\n", + "Re = (v*L)/v1;\t\t\t#Reynolds number\n", + "Nu = (0.677*math.sqrt(Pr)*(0.952+Pr)**(-0.25)*Gr**0.25);\t\t\t#Nusselts number\n", + "h = (Nu*k)/L;\t\t\t#Heat transfer coefficient for natural convection in W/m**2.K\n", + "Nux = (0.664*math.sqrt(Re)*Pr**(1./3));\t\t\t#Nusselts number\n", + "hx = (Nux*k)/L;\t\t\t#Heat transfer coefficient for forced convection in W/m**2.K\n", + "\n", + "# Results\n", + "print 'Heat transfer coefficient for natural convection is %3.1f W/m**2.K \\n \\\n", + "Heat transfer coefficient for forced convection is %3.2f W/m**2.K'%(h,hx)\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Heat transfer coefficient for natural convection is 4.9 W/m**2.K \n", + " Heat transfer coefficient for forced convection is 14.12 W/m**2.K\n" + ] + } + ], + "prompt_number": 3 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.3 Page No : 343" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# Variables\n", + "L = 0.609;\t\t\t#Height of the metal plate in m\n", + "Ts = 161.;\t\t\t#Temperature of the wall in degree C\n", + "Ta = 93.;\t\t\t#Temperature of air in degree C\n", + "\n", + "# Calculations\n", + "Tf = (Ts+Ta)/2;\t\t\t#Film temperature in degree C\n", + "k = 0.0338;\t\t\t#Thermal conductivity in W/m.K\n", + "v1 = (26.4*10**-6);\t\t\t#Kinematic vismath.cosity in m**2/s\n", + "Pr = 0.69;\t\t\t#Prantl number\n", + "b = 0.0025;\t\t\t#Coefficient of thermal expansion in 1./K\n", + "a = (38.3*10**-6);\t\t\t#Thermal diffusivity in m**2/s\n", + "Ra = ((9.81*b*L**3*(Ts-Ta))/(v1*a));\t\t\t#Rayleigh number\n", + "Nu = (0.68+((0.67*Ra**0.25)/(1+(0.492/Pr)**(9./16))**(4./9)));\t\t\t#Nussults number\n", + "h = (Nu*k)/L;\t\t\t#Heat transfer coefficient in W/m**2.K\n", + "Q = (h*L*(Ts-Ta));\t\t\t#Rate of heat transfer in W\n", + "Nul = 0.59 * (3.72*10**8)**(1./4)\n", + "\n", + "# Results\n", + "print 'Heat transfer coefficient is %3.3f W/m**2.K Rate of heat transfer is %3.2f W'%(h,Q)\n", + "print \"NuL = %.2f W\"%Nul" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Heat transfer coefficient is 3.990 W/m**2.K Rate of heat transfer is 165.24 W\n", + "NuL = 81.94 W\n" + ] + } + ], + "prompt_number": 4 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.4 Page No : 344" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# Variables\n", + "W = 0.5;\t\t\t#Width of the radiator in m\n", + "L = 1.;\t\t\t#Height of the radiator in m\n", + "Ts = 84.;\t\t\t#Surface temperature in degree C\n", + "Ta = 20.;\t\t\t#Room temperature in degree C\n", + "\n", + "# Calculations\n", + "Tf = (Ts+Ta)/2;\t\t\t#Film temperature in degree C\n", + "k = 0.02815;\t\t\t#Thermal conductivity in W/m.K\n", + "v1 = (18.41*10**-6);\t\t\t#Kinematic viscosity in m**2/s\n", + "Pr = 0.7;\t\t\t#Prantl number\n", + "b = 0.003077;\t\t\t#Coefficient of thermal expansion in 1./K\n", + "Ra = ((9.81*b*L**3*(Ts-Ta)*Pr)/(v1**2));\t\t\t#Rayleigh number\n", + "Nu = (0.825+((0.387*Ra**(1./6))/(1+(0.492/Pr)**(9./16))**(8./27)))**2;\t\t\t#Nussults number\n", + "h = (1170.9*k)/L;\t\t\t#Heat transfer coefficient in W/m**2.K\n", + "Q = (h*W*L*(Ts-Ta));\t\t\t#Convective heat loss in W\n", + "\n", + "# Results\n", + "print 'Convective heat loss from the radiator is %3.2f W'%(Q)\n", + "\n", + "\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Convective heat loss from the radiator is 1054.75 W\n" + ] + } + ], + "prompt_number": 9 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.5 Page No : 345" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# Variables\n", + "L = 0.8;\t\t\t#Height of the plate in m\n", + "W = 0.08;\t\t\t#Width of the plate in m\n", + "Ts = 170;\t\t\t#Surafce temperature in degree C\n", + "Tw = 70;\t\t\t#Temperature of water in degree C\n", + "Tf = 130;\t\t\t#Final temperature in degree C\n", + "\n", + "# Calculations\n", + "Tb = (Ts+Tw)/2;\t\t\t#Film temperature in degree C\n", + "p = 960.63;\t\t\t#Density in kg/m**3\n", + "k = 0.68;\t\t\t#Thermal conductivity in W/m.K\n", + "v1 = (0.294*10**-6);\t\t\t#Kinematic viscosity in m**2/s\n", + "b = 0.00075;\t\t\t#Coefficient of thermal expansion in 1./K\n", + "Cp = 4216;\t\t\t#Specific heat in J/kg.K\n", + "a = (1.68*10**-7);\t\t\t#Thermal diffusivity in m**2/s\n", + "Lc = (W/2);\t\t\t#Characteristic length in m\n", + "Ra = ((9.81*b*Lc**3*(Tf-Tw))/(v1*a));\t\t\t#Rayleigh number\n", + "Nu1 = (0.15*Ra**(1./3));\t\t\t#Nussults number\n", + "h1 = (Nu1*k)/Lc;\t\t\t#Heat transfer coefficient at top surface in W/m**2.K \n", + "Nu2 = 0.27*(Ra)**(0.25);\t\t\t#Nusselts number\n", + "h2 = (Nu2*k)/Lc;\t\t\t#Heat transfer coefficient at bottom surface in W/m**2.K\n", + "Q = ((h1+h2)*W*L*(Tf-Tw))/1000;\t\t\t#Rate of heat input to the plate in kW\n", + "\n", + "# Results\n", + "print 'Rate of heat input to the plate necessary to maintain the temperature at %3.0f degree C is %3.2f kW'%(Tf,Q)\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Rate of heat input to the plate necessary to maintain the temperature at 130 degree C is 10.85 kW\n" + ] + } + ], + "prompt_number": 6 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.6 Page No : 346" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# Variables\n", + "L = 0.3;\t\t\t#Height of the duct in m\n", + "W = 0.6;\t\t\t#Width of the duct in m\n", + "Ts = 15;\t\t\t#Surface temperature in degree C\n", + "Ta = 25;\t\t\t#Temeprature of air in degree C\n", + "\n", + "# Calculations\n", + "Tb = (Ts+Ta)/2;\t\t\t#Film temperature in degree C\n", + "p = 1.205;\t\t\t#Density in kg/m**3\n", + "k = 0.02593;\t\t\t#Thermal conductivity in W/m.K\n", + "v1 = (15.06*10**-6);\t\t\t#Kinematic viscosity in m**2/s\n", + "b = 0.00341;\t\t\t#Coefficient of thermal expansion in 1./K\n", + "Cp = 1005;\t\t\t#Specific heat in J/kg.K\n", + "Pr = 0.705;\t\t\t#Prantl number\n", + "Ra = ((9.81*b*L**3*(Ta-Ts)*Pr)/(v1**2));\t\t\t#Rayleigh number\n", + "Nux = (0.59*Ra**(0.25));\t\t\t#Nusselts number\n", + "hx = (Nux*k)/L;\t\t\t#Heat transfer coefficient in W/m**2.K\n", + "Lc = (W/2);\t\t\t#Characteristic length in m\n", + "Nu1 = (0.15*Ra**(1./3));\t\t\t#Nussults number\n", + "h1 = (Nu1*k)/Lc;\t\t\t#Heat transfer coefficient at top surface in W/m**2.K \n", + "Nu2 = 0.27*(Ra)**(0.25);\t\t\t#Nusselts number\n", + "h2 = (Nu2*k)/Lc;\t\t\t#Heat transfer coefficient at bottom surface in W/m**2.K\n", + "Q = ((2*hx*L)+(W*(h1+h2)))*(Ta-Ts);\t\t\t#Rate of heat gained per unit length in W/m\n", + "\n", + "# Results\n", + "print 'Rate of heat gained per unit length is %3.2f W/m'%(Q)\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Rate of heat gained per unit length is 56.11 W/m\n" + ] + } + ], + "prompt_number": 7 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.7 Page No : 348" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# Variables\n", + "LH = 0.08;\t\t\t#Horizantal length in m\n", + "LV = 0.12;\t\t\t#Vertical length in m\n", + "Ts = 50;\t\t\t#Surface temperature in degree C\n", + "Ta = 0;\t\t\t#Temeprature of air in degree C\n", + "\n", + "# Calculations\n", + "L = (LH*LV)/(LH+LV);\t\t\t#Characteristic length in m\n", + "Tb = (Ts+Ta)/2;\t\t\t#Film temperature in degree C\n", + "p = 0.707;\t\t\t#Density in kg/m**3\n", + "k = 0.0263;\t\t\t#Thermal conductivity in W/m.K\n", + "v1 = (15.89*10**-6);\t\t\t#Kinematic viscosity in m**2/s\n", + "b = (1./300);\t\t\t#Coefficient of thermal expansion in 1./K\n", + "Pr = 0.707;\t\t\t#Prantl number\n", + "Gr = ((9.81*b*L**3*(Ts-Ta))/(v1**2));\t\t\t#Grashof number\n", + "Nu = 0.55*Gr**(0.25);\t\t\t#Nussults number\n", + "h = (Nu*k)/L;\t\t\t#Heat transfer coefficient in W/m**2.K\n", + "\n", + "# Results\n", + "print 'Heat transfer coefficient is %3.2f W/m**2.K'%(h)\n", + "\n", + "\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Heat transfer coefficient is 8.77 W/m**2.K\n" + ] + } + ], + "prompt_number": 8 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.8 Page No : 349" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# Variables\n", + "D = 0.2;\t\t\t#Outer diameter of the pipe in m\n", + "Ts = 100;\t\t\t#Surface temperature in degree C\n", + "Ta = 20;\t\t\t#Temperature of air in degree C\n", + "L = 3;\t\t\t#Length of pipe in m\n", + "\n", + "# Calculations\n", + "Tf = (Ts+Ta)/2;\t\t\t#Film temperature in degree C\n", + "k = 0.02896;\t\t\t#Thermal conductivity in W/m.K\n", + "v1 = (18.97*10**-6);\t\t\t#Kinematic viscosity in m**2/s\n", + "b = (1./333);\t\t\t#Coefficient of thermal expansion in 1./K\n", + "Pr = 0.696;\t\t\t#Prantl number\n", + "Gr = ((9.81*b*L**3*(Ts-Ta))/(v1**2));\t\t\t#Grashof number\n", + "Ra = (Gr*Pr);\t\t\t#Rayleigh number\n", + "Nu = (0.1*Ra**(1./3));\t\t\t#Nussults number\n", + "h = (Nu*k)/L;\t\t\t#Heat transfer coefficient in W/m**2.K\n", + "Q = (h*3.14*D*(Ts-Ta));\t\t\t#Rate of heat loss per meter length of pipe in W/m\n", + "\n", + "# Results\n", + "print 'Rate of heat loss per meter length of pipe is %3.2f W/m'%(Q)\n", + "\n", + "\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Rate of heat loss per meter length of pipe is 241.24 W/m\n" + ] + } + ], + "prompt_number": 9 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.9 Page No : 350" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# Variables\n", + "D = 0.1;\t\t\t#Outer diamter of the pipe in m\n", + "Ta = 30.;\t\t\t#Ambient temperature of air degree C\n", + "Ts = 170.;\t\t\t#Surface temperature in degree C\n", + "e = 0.9;\t\t\t#Emissivity \n", + "\n", + "# Calculations\n", + "Tb = (Ts+Ta)/2;\t\t\t#Film temperature in degree C\n", + "k = 0.0321;\t\t\t#Thermal conductivity in W/m.K\n", + "v1 = (23.13*10**-6);\t\t\t#Kinematic viscosity in m**2/s\n", + "b = 0.00268;\t\t\t#Coefficient of thermal expansion in 1./K\n", + "Pr = 0.688;\t\t\t#Prantl number\n", + "Ra = ((9.81*b*D**3*(Ts-Ta)*Pr)/(v1**2));\t\t\t#Rayleigh number\n", + "Nu = (0.6+((0.387*Ra**(1./6))/(1+(0.559/Pr)**(9./16))**(8./27)))**2;\t\t\t#Nussults number\n", + "h = (Nu*k)/D;\t\t\t#Heat transfer coefficient in W/m**2.K\n", + "Q = (h*3.1415*D*(Ts-Ta))+(e*3.1415*D*5.67*10**-8*((Ts+273)**4-(Ta+273)**4));\t\t\t#Total heat loss per meter length of pipe in m\n", + "NuD = 0.48*(4.72*10**6)*0.25\n", + "\n", + "# Results\n", + "print 'Total heat loss per meter length of pipe is %3.2f W/m'%(Q)\n", + "print \"NuD = %.2f\"%NuD\n", + "\n", + "# Note : rounding off error.\n", + "# Note : 2nd answer is wrong in book" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Total heat loss per meter length of pipe is 801.20 W/m\n", + "NuD = 566400.00\n" + ] + } + ], + "prompt_number": 16 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.10 Page No : 351" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math\n", + "# Variables\n", + "Ta = 25;\t\t\t#Temperature of air in degree C\n", + "Ts = 95;\t\t\t#Surface temperature of wire in degree C\n", + "D = 0.0025;\t\t\t#Diameter of wire in m\n", + "R = 6;\t\t\t#Resistivity in ohm/m\n", + "\n", + "# Calculations\n", + "Tf = (Ts+Ta)/2;\t\t\t#Film temperature in degree C\n", + "k = 0.02896;\t\t\t#Thermal conductivity in W/m.K\n", + "v1 = (18.97*10**-6);\t\t\t#Kinematic viscosity in m**2/s\n", + "b = (1./333);\t\t\t#Coefficient of thermal expansion in 1./K\n", + "Pr = 0.696;\t\t\t#Prantl number\n", + "Gr = ((9.81*b*D**3*(Ts-Ta))/(v1**2));\t\t\t#Grashof number\n", + "Ra = (Gr*Pr);\t\t\t#Rayleigh number\n", + "Nu = (1.18*Ra**(1./8));\t\t\t#Nussults number\n", + "h = (Nu*k)/D;\t\t\t#Heat transfer coefficient in W/m**2.K\n", + "Q = (h*3.14*D*(Ts-Ta));\t\t\t#Rate of heat loss per unit length of wire in W/m\n", + "I = math.sqrt(Q/R);\t\t\t#Maximum current intensity in A\n", + "\n", + "# Results\n", + "print 'Heat transfer coefficient is %3.2f W/m**2.K \\n \\\n", + "Maximum current intensity is %3.2f A'%(h,I)\n", + "\n", + "\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Heat transfer coefficient is 22.91 W/m**2.K \n", + " Maximum current intensity is 1.45 A\n" + ] + } + ], + "prompt_number": 11 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.11 Page No : 352" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# Variables\n", + "D = 0.01;\t\t\t#Diameter of spherical steel ball in m\n", + "Ts = 260;\t\t\t#Surface temperature in degree C\n", + "Ta = 20;\t\t\t#Temperature of air in degree C\n", + "\n", + "# Calculations\n", + "Tf = (Ts+Ta)/2;\t\t\t#Film temperature in degree C\n", + "k = 0.0349;\t\t\t#Thermal conductivity in W/m.K\n", + "v1 = (27.8*10**-6);\t\t\t#Kinematic viscosity in m**2/s\n", + "b = (1./413);\t\t\t#Coefficient of thermal expansion in 1./K\n", + "Pr = 0.684;\t\t\t#Prantl number\n", + "Ra = ((9.81*b*D**3*(Ts-20)*Pr)/(v1**2));\t\t\t#Rayleigh number\n", + "Nu = (2+(0.43*Ra**0.25));\t\t\t#Nusuults number\n", + "h = (k*Nu)/D;\t\t\t#Heat transfer coefficient in W/m**2.K\n", + "Q = (h*3.14*D**2*(Ts-Ta));\t\t\t#Rate of heat loss in W\n", + "\n", + "# Results\n", + "print 'Rate of convective heat loss is %3.2f W'%(Q)" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Rate of convective heat loss is 1.48 W\n" + ] + } + ], + "prompt_number": 12 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.12 Page No : 353" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# Variables\n", + "D = 0.1;\t\t\t#Outer diamter of the pipe in m\n", + "Ta = 30;\t\t\t#Ambient temperature of air degree C\n", + "Ts = 170;\t\t\t#Surface temperature in degree C\n", + "e = 0.9;\t\t\t#Emissivity \n", + "\n", + "# Calculations\n", + "h = (1.32*((Ts-Ta)/D)**0.25);\t\t\t#Heat transfer coefficient in W/m**2.K\n", + "q = (h*3.1415*D*(Ts-Ta));\t\t\t#Heat transfer in W/m\n", + "\n", + "# Results\n", + "print 'Heat loss due to free convection is %3.2f W/m'%(q)" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Heat loss due to free convection is 355.12 W/m\n" + ] + } + ], + "prompt_number": 13 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.13 Page No : 355" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# Variables\n", + "L = 0.015;\t\t\t#Thickness of the slot in m\n", + "D = 2;\t\t\t#Dimension of square plate in m\n", + "T1 = 120;\t\t\t#Temperature of plate 1\n", + "T2 = 20;\t\t\t#Temperature of plate 2\n", + "\n", + "# Calculations\n", + "Tf = (T1+T2)/2;\t\t\t#Film temperature in degree C\n", + "k = 0.0295;\t\t\t#Thermal conductivity in W/m.K\n", + "v1 = (2*10**-5);\t\t\t#Kinematic viscosity in m**2/s\n", + "b = (1./343);\t\t\t#Coefficient of thermal expansion in 1./K\n", + "Gr = ((9.81*b*L**3*(T1-T2))/(v1**2));\t\t\t#Grashof number\n", + "ke = (0.064*k*Gr**(1./3)*(D/L)**(-1./9));\t\t\t#Effective thermal conductivity in W/m.K\n", + "Q = (ke*D**2*(T1-T2))/L;\t\t\t#Rate of heat transfer in W\n", + "\n", + "# Results\n", + "print 'Effective thermal conductivity is %3.4f W/m.K Rate of heat transfer is %3.1f W'%(ke,Q)" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Effective thermal conductivity is 0.0317 W/m.K Rate of heat transfer is 844.8 W\n" + ] + } + ], + "prompt_number": 15 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.14 Page No : 356" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# Variables\n", + "d = 0.0254;\t\t\t#Diamath.tance between the plates in m\n", + "Tl = 60;\t\t\t#Temperature of the lower panel n degree C\n", + "Tu = 15.6;\t\t\t#Temperature of the upper panel in degree C\n", + "\n", + "# Calculations\n", + "Tf = (Tl+Tu)/2;\t\t\t#Film temperature in degree C\n", + "p = 1.121;\t\t\t#Density in kg/m**3\n", + "k = 0.0292;\t\t\t#Thermal conductivity in W/m.K\n", + "v1 = (0.171*10**-4);\t\t\t#Kinematic viscosity in m**2/s\n", + "b = (3.22*10**-3);\t\t\t#Coefficient of thermal expansion in 1./K\n", + "Pr = 0.7;\t\t\t#Prantl number\n", + "Gr = ((9.81*b*d**3*(Tl-Tu))/(v1**2));\t\t\t#Grashof number\n", + "Nu = (0.195*Gr**0.25);\t\t\t#Nussults number\n", + "q = (Nu*k*(Tl-Tu))/d;\t\t\t#Heat flux across the gap in W/m**2\n", + "\n", + "# Results\n", + "print 'Free convection heat transfer is %3.1f W/m**2'%(q)" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Free convection heat transfer is 166.7 W/m**2\n" + ] + } + ], + "prompt_number": 16 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.15 Page No : 359" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# Variables\n", + "p = 3;\t\t\t#Pressure of air in atm\n", + "r1 = 0.075;\t\t\t#Radius of first sphere in m\n", + "r2 = 0.1;\t\t\t#Radius of second sphere in m\n", + "L = 0.025;\t\t\t#Distance in m\n", + "T1 = 325;\t\t\t#Temperature of first sphere in K\n", + "T2 = 275;\t\t\t#Temperature of second sphere in K\n", + "R = 287;\t\t\t#Universal gas consmath.tant in J/\n", + "\n", + "# Calculations\n", + "Tf = (T1+T2)/2;\t\t\t#Film temperature in degree C\n", + "d = (p/(R*Tf));\t\t\t#Desnsity in kg/m**3\n", + "k = 0.0263;\t\t\t#Thermal conductivity in W/m.K\n", + "v1 = (5.23*10**-6);\t\t\t#Kinematic viscosity in m**2/s\n", + "b = (1./300);\t\t\t#Coefficient of thermal expansion in 1./K\n", + "Pr = 0.707;\t\t\t#Prantl numbe\n", + "Gr = ((9.81*b*L**3*(T1-T2))/(v1**2));\t\t\t#Grashof number\n", + "Ra = (Gr*Pr);\t\t\t#Rayleigh number\n", + "Ra1 = ((L/((4*r1*r2)**4))*(Ra/((2*r1)**(-7./5)+(2*r2)**(-7./5))**5))**0.25;\t\t\t#Equivalent Rayleigh's number\n", + "ke = (k*0.74*((Pr*Ra1)/(0.861+Pr))**0.25);\t\t \t#Effective thermal conductivity in W/m.K\n", + "Q = (ke*3.14*4*r1*r2*(T1-T2))/L;\t\t \t#Rate of heat loss in W\n", + "\n", + "# Results\n", + "print 'Convection heat transfer rate is %3.2f W'%(Q)\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Convection heat transfer rate is 4.92 W\n" + ] + } + ], + "prompt_number": 17 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.16 Page No : 362" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# Variables\n", + "p = 1;\t\t\t#Pressure of air in atm\n", + "Ta = 27;\t\t\t#Temperature of air in degree C\n", + "D = 0.02;\t\t\t#Diamter of the tube in m\n", + "v = 0.3;\t\t\t#Velocity of air in m/s\n", + "Ts = 127;\t\t\t#Surface temperature in degree C\n", + "L = 1;\t\t\t#Length of the tube in m\n", + "\n", + "# Calculations\n", + "k = 0.0262;\t\t\t#Thermal conductivity in W/m.K\n", + "v1 = (1.568*10**-5);\t\t\t#Kinematic viscosity in m**2/s\n", + "Pr = 0.708;\t\t\t#Prantl number\n", + "b = (1./300);\t\t\t#Coefficient of thermal expansion in 1./K\n", + "ub = (1.847*10**-5);\t\t\t#Dynamic viscosity in Ns/m**2\n", + "us = (2.286*10**-5);\t\t\t#Viscosity of wall in Ns/m**2\n", + "Re = (v*D)/v1;\t\t\t#Reynolds number\n", + "Gr = ((9.81*b*D**3*(Ts-Ta))/(v1**2));\t\t\t#Grashof number\n", + "Gz = (Re*Pr*(D/L));\t\t\t#Graetz number\n", + "Nu = (1.75*(ub/us)**0.14*(Gz+(0.012*(Gz*Gr**(1./3))**(4./3)))**(1./3));\t\t\t#Nussults number\n", + "h = (k*Nu)/D;\t\t\t#Heat transfer coefficient in W/m**2.K\n", + "Q = (h*3.14*D*L*(Ts-Ta));\t\t\t#Heat transfer in W\n", + "\n", + "# Results\n", + "print 'Heat transfer in the tube is %3.2f W'%(Q)" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Heat transfer in the tube is 40.86 W\n" + ] + } + ], + "prompt_number": 18 + } + ], + "metadata": {} + } + ] +}
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