diff options
author | Trupti Kini | 2017-01-10 23:30:44 +0600 |
---|---|---|
committer | Trupti Kini | 2017-01-10 23:30:44 +0600 |
commit | 882a643ff3426d410a375df9c18ae2f90e045728 (patch) | |
tree | fb761bc73ea8a25d2a7814334955872baaa616bd /Introduction_to_Heat_Transfer_by_S._K._Som/Chapter8.ipynb | |
parent | f3b30a82c058596a9c865251f1cf22540efdf777 (diff) | |
download | Python-Textbook-Companions-882a643ff3426d410a375df9c18ae2f90e045728.tar.gz Python-Textbook-Companions-882a643ff3426d410a375df9c18ae2f90e045728.tar.bz2 Python-Textbook-Companions-882a643ff3426d410a375df9c18ae2f90e045728.zip |
Added(A)/Deleted(D) following books
A Introduction_to_Heat_Transfer_by_S._K._Som/Chapter1.ipynb
A Introduction_to_Heat_Transfer_by_S._K._Som/Chapter10.ipynb
A Introduction_to_Heat_Transfer_by_S._K._Som/Chapter11.ipynb
A Introduction_to_Heat_Transfer_by_S._K._Som/Chapter2.ipynb
A Introduction_to_Heat_Transfer_by_S._K._Som/Chapter3.ipynb
A Introduction_to_Heat_Transfer_by_S._K._Som/Chapter4.ipynb
A Introduction_to_Heat_Transfer_by_S._K._Som/Chapter5.ipynb
A Introduction_to_Heat_Transfer_by_S._K._Som/Chapter6.ipynb
A Introduction_to_Heat_Transfer_by_S._K._Som/Chapter7.ipynb
A Introduction_to_Heat_Transfer_by_S._K._Som/Chapter8.ipynb
A Introduction_to_Heat_Transfer_by_S._K._Som/Chapter9.ipynb
A Introduction_to_Heat_Transfer_by_S._K._Som/chapter12.ipynb
A Introduction_to_Heat_Transfer_by_S._K._Som/screenshots/9.7.png
A Introduction_to_Heat_Transfer_by_S._K._Som/screenshots/Ex10.7.png
A Introduction_to_Heat_Transfer_by_S._K._Som/screenshots/Ex11.4.png
A Thermodynamics,_Statistical_Thermodynamic_and_Kinetics_by_T._Engel_and_P._Reid/Chapter01.ipynb
A Thermodynamics,_Statistical_Thermodynamic_and_Kinetics_by_T._Engel_and_P._Reid/Chapter02.ipynb
A Thermodynamics,_Statistical_Thermodynamic_and_Kinetics_by_T._Engel_and_P._Reid/Chapter03.ipynb
A Thermodynamics,_Statistical_Thermodynamic_and_Kinetics_by_T._Engel_and_P._Reid/Chapter04.ipynb
A Thermodynamics,_Statistical_Thermodynamic_and_Kinetics_by_T._Engel_and_P._Reid/Chapter05.ipynb
A Thermodynamics,_Statistical_Thermodynamic_and_Kinetics_by_T._Engel_and_P._Reid/Chapter06.ipynb
A Thermodynamics,_Statistical_Thermodynamic_and_Kinetics_by_T._Engel_and_P._Reid/Chapter07.ipynb
A Thermodynamics,_Statistical_Thermodynamic_and_Kinetics_by_T._Engel_and_P._Reid/Chapter08.ipynb
A Thermodynamics,_Statistical_Thermodynamic_and_Kinetics_by_T._Engel_and_P._Reid/Chapter09.ipynb
A Thermodynamics,_Statistical_Thermodynamic_and_Kinetics_by_T._Engel_and_P._Reid/Chapter10.ipynb
A Thermodynamics,_Statistical_Thermodynamic_and_Kinetics_by_T._Engel_and_P._Reid/Chapter11.ipynb
A Thermodynamics,_Statistical_Thermodynamic_and_Kinetics_by_T._Engel_and_P._Reid/Chapter12.ipynb
A Thermodynamics,_Statistical_Thermodynamic_and_Kinetics_by_T._Engel_and_P._Reid/Chapter13.ipynb
A Thermodynamics,_Statistical_Thermodynamic_and_Kinetics_by_T._Engel_and_P._Reid/Chapter14.ipynb
A Thermodynamics,_Statistical_Thermodynamic_and_Kinetics_by_T._Engel_and_P._Reid/Chapter15.ipynb
A Thermodynamics,_Statistical_Thermodynamic_and_Kinetics_by_T._Engel_and_P._Reid/Chapter16.ipynb
A Thermodynamics,_Statistical_Thermodynamic_and_Kinetics_by_T._Engel_and_P._Reid/Chapter17.ipynb
A Thermodynamics,_Statistical_Thermodynamic_and_Kinetics_by_T._Engel_and_P._Reid/Chapter18.ipynb
A Thermodynamics,_Statistical_Thermodynamic_and_Kinetics_by_T._Engel_and_P._Reid/Chapter19.ipynb
A Thermodynamics,_Statistical_Thermodynamic_and_Kinetics_by_T._Engel_and_P._Reid/screenshots/15.8.png
A Thermodynamics,_Statistical_Thermodynamic_and_Kinetics_by_T._Engel_and_P._Reid/screenshots/4.3.png
A Thermodynamics,_Statistical_Thermodynamic_and_Kinetics_by_T._Engel_and_P._Reid/screenshots/9.6.png
A Thermodynamics,_Statistical_Thermodynamics_and_Kinetics_by_T._Engel_and_P._Reid/Chapte_5AfCLKz.ipynb
A Thermodynamics,_Statistical_Thermodynamics_and_Kinetics_by_T._Engel_and_P._Reid/Chapte_9c27zxN.ipynb
A Thermodynamics,_Statistical_Thermodynamics_and_Kinetics_by_T._Engel_and_P._Reid/Chapte_9cObgYn.ipynb
A Thermodynamics,_Statistical_Thermodynamics_and_Kinetics_by_T._Engel_and_P._Reid/Chapte_9ui5Wjm.ipynb
A Thermodynamics,_Statistical_Thermodynamics_and_Kinetics_by_T._Engel_and_P._Reid/Chapte_JaqgDu7.ipynb
A Thermodynamics,_Statistical_Thermodynamics_and_Kinetics_by_T._Engel_and_P._Reid/Chapte_MnetfXH.ipynb
A Thermodynamics,_Statistical_Thermodynamics_and_Kinetics_by_T._Engel_and_P._Reid/Chapte_N5LVZdn.ipynb
A Thermodynamics,_Statistical_Thermodynamics_and_Kinetics_by_T._Engel_and_P._Reid/Chapte_NEmIMzZ.ipynb
A Thermodynamics,_Statistical_Thermodynamics_and_Kinetics_by_T._Engel_and_P._Reid/Chapte_NaQvqio.ipynb
A Thermodynamics,_Statistical_Thermodynamics_and_Kinetics_by_T._Engel_and_P._Reid/Chapte_Npcu1fX.ipynb
A Thermodynamics,_Statistical_Thermodynamics_and_Kinetics_by_T._Engel_and_P._Reid/Chapte_SSPoRzJ.ipynb
A Thermodynamics,_Statistical_Thermodynamics_and_Kinetics_by_T._Engel_and_P._Reid/Chapte_WJvqX73.ipynb
A Thermodynamics,_Statistical_Thermodynamics_and_Kinetics_by_T._Engel_and_P._Reid/Chapte_cyWVjGT.ipynb
A Thermodynamics,_Statistical_Thermodynamics_and_Kinetics_by_T._Engel_and_P._Reid/Chapte_eAEoe4s.ipynb
A Thermodynamics,_Statistical_Thermodynamics_and_Kinetics_by_T._Engel_and_P._Reid/Chapte_ezyRCsC.ipynb
A Thermodynamics,_Statistical_Thermodynamics_and_Kinetics_by_T._Engel_and_P._Reid/Chapte_jHUJFvU.ipynb
A Thermodynamics,_Statistical_Thermodynamics_and_Kinetics_by_T._Engel_and_P._Reid/Chapte_rQOLXRQ.ipynb
A Thermodynamics,_Statistical_Thermodynamics_and_Kinetics_by_T._Engel_and_P._Reid/Chapte_vVWK1Pz.ipynb
A Thermodynamics,_Statistical_Thermodynamics_and_Kinetics_by_T._Engel_and_P._Reid/Chapte_ys4AGAJ.ipynb
Diffstat (limited to 'Introduction_to_Heat_Transfer_by_S._K._Som/Chapter8.ipynb')
-rw-r--r-- | Introduction_to_Heat_Transfer_by_S._K._Som/Chapter8.ipynb | 893 |
1 files changed, 893 insertions, 0 deletions
diff --git a/Introduction_to_Heat_Transfer_by_S._K._Som/Chapter8.ipynb b/Introduction_to_Heat_Transfer_by_S._K._Som/Chapter8.ipynb new file mode 100644 index 00000000..a6c237e4 --- /dev/null +++ b/Introduction_to_Heat_Transfer_by_S._K._Som/Chapter8.ipynb @@ -0,0 +1,893 @@ +{ + "cells": [ + { + "cell_type": "markdown", + "metadata": { + "collapsed": true + }, + "source": [ + "# Chapter 08:Principles of free convection" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Ex8.1:pg-355" + ] + }, + { + "cell_type": "code", + "execution_count": 1, + "metadata": { + "collapsed": false + }, + "outputs": [ + { + "name": "stdout", + "output_type": "stream", + "text": [ + "Introduction to heat transfer by S.K.Som, Chapter 8, Example 1\n", + "Grashoff number is\n", + "GrL= 2175146201.53\n", + "Rayleigh number is\n", + "RaL= 9440134514.65\n", + "Therefore the flow is turbulent\n", + "Now we use [(hbarL*L)/k]=0.10*(GrL*Pr)**(1/3)\n", + "The average heat transfer coefficient in W/(m**2*K) is\n", + "hbarL= 0.314\n", + "The rate of heat transfer in W is\n", + "q= 0.5024\n" + ] + } + ], + "source": [ + "import math \n", + " \n", + "print\"Introduction to heat transfer by S.K.Som, Chapter 8, Example 1\"\n", + "#Water is heated by a vertical flat plate length(L=200mm or .2m )by breadth(B=200mm) which is maintained at temprature,Tw=60°C\n", + "Tw=60;\n", + "L=.2;\n", + "B=.2;# in metre\n", + "#Area(A) is L*B \n", + "A=L*B;\n", + "#Water is at temprature,Tinf=20°C\n", + "Tinf=20;\n", + "#At mean film temprature 40°C The physical properties parameters can be taken as \n", + "#conductivity(k=0.0628W/(m*K)),Prandtl number(Pr=4.34),density(rho=994.59kg/m**3),kinematic viscosity(nu=0.658*10**-6m**2/s),volume expnasion coefficient(Beta=3*10**-4K**-1))\n", + "k=0.628;\n", + "Pr=4.34;\n", + "rho=994.59;\n", + "nu=0.658*10**-6;\n", + "Beta=3*10**-4;\n", + "#g is acceleration due to gravity =9.81m/s**2\n", + "g=9.81;\n", + "#Grashoff number is given by GrL=(g*beta*(Tw-Tinf)*L**3)/(nu)**2\n", + "print\"Grashoff number is\"\n", + "GrL=(g*Beta*(Tw-Tinf)*L**3)/(nu)**2\n", + "print\"GrL=\",GrL\n", + "#Rayleigh number is defined as RaL=GrL*Pr\n", + "print\"Rayleigh number is\"\n", + "RaL=GrL*Pr\n", + "print\"RaL=\",RaL\n", + "print\"Therefore the flow is turbulent\"\n", + "print\"Now we use [(hbarL*L)/k]=0.10*(GrL*Pr)**(1/3)\"\n", + "#hbarL is the average heat transfer coefficient\n", + "print\"The average heat transfer coefficient in W/(m**2*K) is\"\n", + "hbarL=(0.10*(GrL*Pr)**(1/3)*k)/L\n", + "print\"hbarL=\",hbarL\n", + "#The rate of heat transfer is given by q=hbarL*A*(Tw-Tinf)\n", + "print\"The rate of heat transfer in W is\"\n", + "q=hbarL*A*(Tw-Tinf)\n", + "print\"q=\",q\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Ex8.2:pg-357" + ] + }, + { + "cell_type": "code", + "execution_count": 2, + "metadata": { + "collapsed": false + }, + "outputs": [ + { + "name": "stdout", + "output_type": "stream", + "text": [ + "Introduction to heat transfer by S.K.Som, Chapter 8, Example 2\n", + "The minimum spacing between the plates will be twice the thickness of the boundary layer at the trailing edge where x=0.09\n", + "Grashoff number is\n", + "GrL= 198210197.615\n", + "Rayleigh number is\n", + "RaL= 860232257.647\n", + "Since Ra<10**9,Therefore the flow is laminar\n", + "The thickness of the boundary layer in metre is\n", + "delta= 4.11168026839e-10\n", + "The minimum spacing in metre is\n", + "spac= 8.22336053678e-10\n" + ] + } + ], + "source": [ + " \n", + "import math \n", + " \n", + "print\"Introduction to heat transfer by S.K.Som, Chapter 8, Example 2\"\n", + "#The thin plates are kept at temprature(Tw)=60°C while the temprature of water bath(Tinf)=20°C\n", + "Tw=60;\n", + "Tinf=20;\n", + "#The plates have length(L)=90mm or .09m\n", + "L=.09;\n", + "#The minimum spacing between the plates will be twice the thickness of the boundary layer at the trailing edge where x=0.09.\n", + "print\"The minimum spacing between the plates will be twice the thickness of the boundary layer at the trailing edge where x=0.09\"\n", + "x=.09;\n", + "#At mean film temprature 40°C The physical properties parameters can be taken as\n", + "# conducivity(k=0.0628W/(m*K)),Prandtl number(Pr=4.34),Density(rho=994.59kg/m**3),kinematic viscosity(nu=0.658*10**-6m**2/s),Volume expansion coefficient(Beta=3*10**-4K**-1)\n", + "k=0.628;\n", + "Pr=4.34;\n", + "rho=994.59;\n", + "nu=0.658*10**-6;\n", + "Beta=3*10**-4;\n", + "#g is acceleration due to gravity =9.81m/s**2\n", + "g=9.81;\n", + "#Grashoff number is given by GrL=(g*beta*(Tw-Tinf)*L**3)/(nu)**2\n", + "print\"Grashoff number is\"\n", + "GrL=(g*Beta*(Tw-Tinf)*L**3)/(nu)**2\n", + "print\"GrL=\",GrL\n", + "#Rayleigh number is defined as RaL=GrL*Pr\n", + "print\"Rayleigh number is\"\n", + "RaL=GrL*Pr\n", + "print\"RaL=\",RaL\n", + "print\"Since Ra<10**9,Therefore the flow is laminar\"\n", + "#delta is the thickness of the boundary layer\n", + "print\"The thickness of the boundary layer in metre is\"\n", + "delta=x*3.93*Pr**(-1/2)*(0.952+Pr)**(1/4)*GrL**(-1/4)\n", + "print\"delta=\",delta\n", + "#spac is the minimum spacing \n", + "print\"The minimum spacing in metre is\"\n", + "spac=2*delta\n", + "print\"spac=\",spac\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Ex8.3:pg-366" + ] + }, + { + "cell_type": "code", + "execution_count": 3, + "metadata": { + "collapsed": false + }, + "outputs": [ + { + "name": "stdout", + "output_type": "stream", + "text": [ + "Introduction to heat transfer by S.K.Som, Chapter 8, Example 3\n", + "Grashoff number is\n", + "Grx= 517025.52213\n", + "The boundary layer thickness in metre is\n", + "delta= 60304.3038858\n", + "The velocity at point x is ux in m/s is\n", + "ux= 3247798354.51\n", + "For maximum value of velocity,u\n", + "Maximum velocity in m/s is\n", + "Umax= 3.57089835848\n", + "Mass flow rate at x=0.8m,in kG is\n", + "mdot= 2.36830073295e+16\n" + ] + } + ], + "source": [ + "\n", + "from scipy.integrate import quad\n", + "print \"Introduction to heat transfer by S.K.Som, Chapter 8, Example 3\"\n", + "#Considering question 5.7\n", + "#A wall is exposed to nitrogen at one atmospheric pressure and temprature,Tinf=4°C.\n", + "Tinf=4.0;\n", + "#The wall is H=2.0m high and 2.5m wide and is maintained at temprature,Tw=56°C\n", + "Tw=56.0;\n", + "H=2.0;\n", + "B=2.5;\n", + "A=H*B;#Area of wall in m**2\n", + "#The properties of nitrogen at mean film temprature (56+4)/2=30°C are given as \n", + "#density(rho=1.142kg/m*3) ,conductivity(k=0.026W/(m*K)),kinematic viscosity(nu=15.630*10-6 m*2/s) ,prandtl number(Pr=0.713)\n", + "rho=1.142;\n", + "k=0.026;\n", + "nu=15.630*10**-6;\n", + "Pr=0.713;\n", + "Tf=30.0;#mean film temprature\n", + "Beta=1/(273.0+Tf);#volume expansion coefficient:unit K**-1\n", + "#Now Grashoff number is Grx=(g*Beta*(Tw-Tinf)*x*3)/nu*2\n", + "g=9.81;#acceleration due to gravity\n", + "print \"Grashoff number is\"\n", + "x=0.8;#distance from the bottom of wall\n", + "Grx=(g*Beta*(Tw-Tinf)*x*3)/nu*2\n", + "print\"Grx=\",Grx\n", + "#Using equation delta=x*Pr*(-0.5)(0.952+Pr)*(0.25)*Grx*(-0.25)\n", + "#delta is the boundary layer thickness\n", + "print \"The boundary layer thickness in metre is\"\n", + "delta=x*3.93*Pr*(-0.5)*(0.952+Pr)*(0.25)*Grx*(-0.25)\n", + "print\"delta=\",delta\n", + "#Now using equation ux=(g*Beta*delta*2(Tw-Tinf))/(4*nu)\n", + "#ux is the velocity at point x\n", + "print \"The velocity at point x is ux in m/s is\"\n", + "ux=(g*Beta*delta*2*(Tw-Tinf))/(4*nu)\n", + "print\"ux=\",ux\n", + "# (u/ux)=(y/delta)*(1-y/delta)**2\n", + "#Putting value of ux we get velovity function,u=465.9*(y-116*y*2+3341*y*3)\n", + "#For maximum value of u,du/dy=465.9*(1-232*y+10023*y**2)=0...this is a quadratic equation in which coefficients a=10023,b=232,c=1\n", + "a=10023;\n", + "b=232;\n", + "c=1;\n", + "#Solution for quadratic equation is given by y=(-b+-(b*2-4ac)*0.5)/2*a\n", + "print \"For maximum value of velocity,u\"\n", + "y=(b+(b*2-4*a*c)*0.5)/(2*a)#root of the quadratic equation\n", + "y=(b-(b*2-4*a*c)*0.5)/(2*a)#root of the quadratic equation\n", + "#The value of 0.0173 is at the edge of boundary layer,where u=0\n", + "#Therefore the maximum value occurs at y=0.00573m i.e Umax=465.9*y*(1-57.8*y)**2\n", + "y=0.00573;\n", + "#Umax is maximum velocity\n", + "print \"Maximum velocity in m/s is\"\n", + "Umax=465.9*y*(1-57.8*y)*2#NOTE:The answer given in the book is incorrect,in this expresssion they considered square on y only,however it is on whole expression (1-57.8*y)*2\n", + "#mdot is mass flow rate\n", + "print\"Umax=\",Umax\n", + "print \"Mass flow rate at x=0.8m,in kG is\"\n", + "I=quad(lambda y:465.9*(y-116*y*2+3341*y*3),0,delta)\n", + "mdot=rho*B*I[0]\n", + "print\"mdot=\",mdot\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Ex8.4:pg-369" + ] + }, + { + "cell_type": "code", + "execution_count": 11, + "metadata": { + "collapsed": false + }, + "outputs": [ + { + "name": "stdout", + "output_type": "stream", + "text": [ + "Introduction to heat transfer by S.K.Som, Chapter 8, Example 4\n", + "Grashoff number is\n", + "Rayleigh number is\n", + "Hence,the flow is laminar\n", + "The thickness of the boundary layer in metre is\n", + "The average heat transfer coeficient in W/(m**2*K) is\n", + "0.101781170483\n" + ] + } + ], + "source": [ + " \n", + "import math \n", + " \n", + "print\"Introduction to heat transfer by S.K.Som, Chapter 8, Example 4\"\n", + "#A square plate length,L=0.2m by breadth,B=0.2m is suspended vertically in a quiescent atmospheric air at a temprature(Tinf)=300K\n", + "L=0.2;\n", + "B=0.2;\n", + "Tinf=300;\n", + "#The Temprature of plate(Tw) is maintained at 400K\n", + "Tw=400;\n", + "#The required property value of air at a film temprature(Tf)=350K,kinematic viscosity (nu=20.75*10**-6),Prandtl number(Pr=0.69),conductivity(k=0.03W/(m*K))\n", + "Tf=350;\n", + "nu=20.75*10**-6;\n", + "Pr=0.69;\n", + "k=0.03;\n", + "#volume expansion coefficient is Beta\n", + "Beta=(1/Tf);\n", + "#g is acceleration due to gravity =9.81m/s**2\n", + "g=9.81;\n", + "#Grashoff number is given by GrL=(g*beta*(Tw-Tinf)*L**3)/(nu)**2\n", + "print\"Grashoff number is\"\n", + "GrL=(g*Beta*(Tw-Tinf)*L**3)/(nu)**2 \n", + "print\"GrL=\",GrL\n", + "#Rayleigh number is defined as RaL=GrL*Pr\n", + "print\"Rayleigh number is\"\n", + "RaL=GrL*Pr\n", + "print\"Hence,the flow is laminar\"\n", + "print\"RaL=\",RaL\n", + "#delta is the thickness of the boundary layer\n", + "print\"The thickness of the boundary layer in metre is\"\n", + "x=0.2;#location of trailing edge of plate\n", + "delta=(x*3.93*(0.952+Pr)**(1/4))/(Pr**(1/2)*(GrL)**(1/4))#NOTE:The answer in the book is incorrect(calculation mistake)\n", + "print\"delta=\",delta\n", + "#hL and hbarL are local and average heat transfer coefficient respectively\n", + "print\"The average heat transfer coeficient in W/(m**2*K) is\"\n", + "hL=(2*k)/delta;\n", + "hbarL=(4.0/3)*(hL)#NOTE:The answer in the book is incorrect(calculation mistake)\n", + "print\"hL=\",hL\n", + "print\"hbarL=\",hbarL\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Ex8.5:pg-373" + ] + }, + { + "cell_type": "code", + "execution_count": 4, + "metadata": { + "collapsed": false + }, + "outputs": [ + { + "name": "stdout", + "output_type": "stream", + "text": [ + "Introduction to heat transfer by S.K.Som, Chapter 8, Example 5\n", + "Grashoff number is\n", + "503958851.066\n", + "Rayleigh number is\n", + "357810784.257\n", + "Therefore the flow is laminar\n", + "Nusselt number is\n", + "75.3134665126\n", + "Average heat transfer coefficient(hbarL)in W/(m**2*°C)\n", + "The rate of heat transfer in W is \n", + "Now if we use NuL2=0.59*RaL**(1/4) with the value of C=0.59,n=(1/4)\n", + "Nusselt number is\n", + "Average heat transfer coefficient(hbarL)in W/(m**2*°C)\n", + "The rate of heat transfer in W is \n", + "49.9857347505\n", + "(b)For the horizontal plate facing up\n", + "Now RaL2=Gr*Pr*(Lc/L)**3\n", + "Rayleigh number is\n", + "Nusselt number is given by NuL3=C*(GrL*Pr)**n\n", + "Average heat transfer coefficient(hbarL)in W/(m**2*°C)\n", + "The rate of heat transfer in W is \n", + "64.6997833306\n", + "(c)When the hot surface faces is down\n", + "Nusselt number is given by NuL4=0.27*RaL2**(1/4)\n", + "13.1290144745\n", + "Average heat transfer coefficient(hbarL) in W/(m**2)\n", + "2.9408992423\n", + "The rate of heat transfer in W is \n", + "32.3498916653\n" + ] + } + ], + "source": [ + " \n", + "import math \n", + " \n", + "print\"Introduction to heat transfer by S.K.Som, Chapter 8, Example 5\"\n", + "#A square plate of length(L)=0.5m by breadth,B=0.5m in a room at temprature,Tinf=30°C\n", + "#One side of plate is kept a uniform temprature(Tw)=74°C\n", + "Tw=74;\n", + "L=0.5;\n", + "B=0.5;\n", + "Tinf=30.0;\n", + "#The required properties at the film temprature(Tf)=52°C are kinematic viscosity(nu=1.815*10**-5),Prandtl number(Pr=0.71),conductivity(k=0.028W/(m*°C))\n", + "Tf=52.0;\n", + "Pr=0.71;\n", + "nu=1.815*10**-5;\n", + "k=0.028;\n", + "#Area(A)=L*B m**2\n", + "A=L*B;\n", + "#Volume expansion coefficient is Beta\n", + "Beta=1/(273+Tf);\n", + "#g is acceleration due to gravity =9.81m/s**2\n", + "g=9.81;\n", + "#Grashoff number is given by GrL=(g*beta*(Tw-Tinf)*L**3)/(nu)**2\n", + "print\"Grashoff number is\"\n", + "GrL=(g*Beta*(Tw-Tinf)*L**3)/(nu)**2 \n", + "print GrL\n", + "#Rayleigh number is defined as RaL1=GrL*Pr\n", + "print\"Rayleigh number is\"\n", + "RaL1=GrL*Pr\n", + "print RaL1\n", + "print\"Therefore the flow is laminar\"\n", + "#We make use of following equation to find Nusselt number,NuL1=(4/3)*(0.508*Pr**(-1/2)*(0.952+Pr)**(-1/4)*Gr**(1/4))\n", + "print\"Nusselt number is\"\n", + "NuL1=(4.0/3)*(0.508*Pr**(1.0/2)*(0.952+Pr)**(-1.0/4)*GrL**(1.0/4))\n", + "#Average heat transfer coefficient(hbarL) is given by (NuL*k)/L\n", + "print NuL1\n", + "print\"Average heat transfer coefficient(hbarL)in W/(m**2*°C)\"\n", + "hbarL=(NuL1*k)/L\n", + "#The rate of heat transfer(Q) from the plate by free convection is given by Q=hbarL*A*(Tw-Tinf)\n", + "print\"The rate of heat transfer in W is \"\n", + "Q=hbarL*A*(Tw-Tinf)\n", + "print\"Now if we use NuL2=0.59*RaL**(1/4) with the value of C=0.59,n=(1/4)\"\n", + "print\"Nusselt number is\"\n", + "NuL2=0.59*RaL1**(1.0/4)\n", + "#Average heat transfer coefficient(hbarL) is given by (NuL*k)/L\n", + "print\"Average heat transfer coefficient(hbarL)in W/(m**2*°C)\"\n", + "hbarL=(NuL2*k)/L\n", + "#The rate of heat transfer(Q) from the plate by free convection is given by Q=hbarL*A*(Tw-Tinf)\n", + "print\"The rate of heat transfer in W is \"\n", + "Q=hbarL*A*(Tw-Tinf)\n", + "print Q\n", + "print\"(b)For the horizontal plate facing up\"\n", + "#Perimeter(P) for a square plate is P=4*L\n", + "P=4*L;\n", + "#Characterstic length(Lc)=A/P\n", + "Lc=A/P\n", + "print\"Now RaL2=Gr*Pr*(Lc/L)**3\"\n", + "print\"Rayleigh number is\"\n", + "RaL2=GrL*Pr*(Lc/L)**3\n", + "#The values of constants,C=0.54 and n=(1/4)\n", + "C=0.54;\n", + "n=(1.0/4);\n", + "print\"Nusselt number is given by NuL3=C*(GrL*Pr)**n\"\n", + "NuL3=C*(RaL2)**n\n", + "print\"Average heat transfer coefficient(hbarL)in W/(m**2*°C)\"\n", + "hbarL=(NuL3*k)/Lc\n", + "print\"The rate of heat transfer in W is \"\n", + "Q=hbarL*A*(Tw-Tinf)\n", + "print Q\n", + "print\"(c)When the hot surface faces is down\"\n", + "print\"Nusselt number is given by NuL4=0.27*RaL2**(1/4)\"\n", + "NuL4=0.27*RaL2**(1.0/4)\n", + "print NuL4\n", + "print\"Average heat transfer coefficient(hbarL) in W/(m**2)\"\n", + "hbarL=(NuL4*k)/Lc\n", + "print hbarL\n", + "print\"The rate of heat transfer in W is \"\n", + "Q=hbarL*A*(Tw-Tinf)\n", + "print Q\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Ex8.6:pg-375" + ] + }, + { + "cell_type": "code", + "execution_count": 5, + "metadata": { + "collapsed": false + }, + "outputs": [ + { + "name": "stdout", + "output_type": "stream", + "text": [ + "Introduction to heat transfer by S.K.Som, Chapter 8, Example 6\n", + "Grashoff number is\n", + "GrL= 813719594.384\n", + "Rayleigh number is\n", + "RaL= 569603716.069\n", + "Therefore the flow is laminar\n", + "Now we use NuL=0.59*RaL**(1/4.0) with the value of constants C=0.59,n=(1/4.0)\n", + "Nusselt number is\n", + "NuL= 91.1475952489\n", + "Average heat transfer coefficient in W/(m**2*K)\n", + "hbarL1= 5.46885571493\n", + "Grashoff number GrD=GrL*(D/L)**3\n", + "GrD= 0.00650975675508\n", + "The correction factor is\n", + "F= 39.485281111\n", + "The correct value of Average heat transfer coefficient(hbarL2)=hbarL1*F in W/(m**2*K) is\n", + "hbarL2= 215.939305259\n", + "The ohmic loss in W is \n", + "q= 3.39196667512\n", + "The current flowing in the wire in Ampere is\n", + "I= 7.51882822777\n" + ] + } + ], + "source": [ + " \n", + " \n", + " \n", + " \n", + "import math \n", + " \n", + "print\"Introduction to heat transfer by S.K.Som, Chapter 8, Example 6\"\n", + "#A vertical wire of length(L)=0.5m and Dimeter(D)=0.1mm is maintained at temprature, Tw=400K\n", + "#The temprature of quicsent air is Tinf=300K\n", + "#Resistance(R) per meter length is 0.12ohm\n", + "R=0.12;\n", + "Tw=400.0;\n", + "L=0.5;\n", + "D=0.1*10**-3;#in metre\n", + "Tinf=300;\n", + "#The required properties at the film temprature(Tf)=350K are kinematic viscosity(nu=20.75*10**-6m**2/s),Prandtl number(Pr=0.70),conductivity(k=0.03W/(m*°C))\n", + "Tf=350.0;\n", + "Pr=0.70;\n", + "nu=20.75*10**-6;\n", + "k=0.03;\n", + "#Area(A)=L*B m**2\n", + "A=math.pi*D*L;\n", + "#Volume expansion Coefficient is Beta\n", + "Beta=1/(Tf);\n", + "#g is acceleration due to gravity =9.81m/s**2\n", + "g=9.81;\n", + "#Grashoff number is given by GrL=(g*beta*(Tw-Tinf)*L**3)/(nu)**2\n", + "print\"Grashoff number is\"\n", + "GrL=(g*Beta*(Tw-Tinf)*L**3)/(nu)**2 \n", + "print\"GrL=\",GrL\n", + "#Rayleigh number is defined as RaL=GrL*Pr\n", + "print\"Rayleigh number is\"\n", + "RaL=GrL*Pr\n", + "print\"RaL=\",RaL\n", + "print\"Therefore the flow is laminar\"\n", + "#NuL is nusselt number\n", + "#C and n are constants\n", + "print\"Now we use NuL=0.59*RaL**(1/4.0) with the value of constants C=0.59,n=(1/4.0)\"\n", + "print\"Nusselt number is\"\n", + "NuL=0.59*RaL**(1/4.0)\n", + "print\"NuL=\",NuL\n", + "#hbarL1 is the Average heat transfer coefficient\n", + "print\"Average heat transfer coefficient in W/(m**2*K)\"\n", + "hbarL1=(NuL*k)/L\n", + "print\"hbarL1=\",hbarL1\n", + "#Grashoff number GrD=GrL*(D/L)**3\n", + "print\"Grashoff number GrD=GrL*(D/L)**3\"\n", + "GrD=GrL*(D/L)**3\n", + "print\"GrD=\",GrD\n", + "#The correction factor is given By F=1.3*((L/D)/GrD)**(1/4.0)+1.0\n", + "print\"The correction factor is\"\n", + "F=1.3*((L/D)/GrD)**(1/4.0)+1.0\n", + "print\"F=\",F\n", + "print\"The correct value of Average heat transfer coefficient(hbarL2)=hbarL1*F in W/(m**2*K) is\"\n", + "hbarL2=hbarL1*F\n", + "print\"hbarL2=\",hbarL2\n", + "#The ohmic power loss is given by energy balance I**2*R=q=hbar2*A*(Tw-Tinf)\n", + "#q is the ohmic power loss\n", + "print\"The ohmic loss in W is \"\n", + "q=hbarL2*A*(Tw-Tinf)\n", + "print\"q=\",q\n", + "#The current flowing in the wire I=(q/(R*L)**(1/2.0)\n", + "print\"The current flowing in the wire in Ampere is\"\n", + "I=(q/(R*L))**(1/2.0)\n", + "print\"I=\",I\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Ex8.7:pg-378" + ] + }, + { + "cell_type": "code", + "execution_count": 6, + "metadata": { + "collapsed": false + }, + "outputs": [ + { + "name": "stdout", + "output_type": "stream", + "text": [ + "Introduction to heat transfer by S.K.Som, Chapter 8, Example 7\n", + "Grashoff number is\n", + "GrD= 53311595.6796\n", + "Rayleigh number is\n", + "RaD= 37318116.9757\n", + "The flow is laminar over the entire cylinder\n", + "we use following equation to find Nusselt number NuD=(0.60+((0.387*RaD**(1/6))/(1+(0.559/Pr**(9/16)))**(8/27)))**2\n", + "NuD= 0.974169\n", + "Average heat transfer coefficient in W/(m**2*K)\n", + "hbar= 0.14612535\n", + "The heat loss per meter length in W is\n", + "q= 9.64039284733\n" + ] + } + ], + "source": [ + " \n", + "import math \n", + " \n", + "print\"Introduction to heat transfer by S.K.Som, Chapter 8, Example 7\"\n", + "#A long horizontal pressurized hot water of diameter(D)=200mm passes through a room where the air temprature is Tinf=25°C\n", + "D=.2;\n", + "Tinf=25;\n", + "#Length(L)=1m ,since the unit length is considered\n", + "L=1;\n", + "#Area(A)=pi*L*D\n", + "A=math.pi*L*D;\n", + "#The pipe surface temprature is Tw=130°C\n", + "Tw=130;\n", + "#The properties of air at the film temprature Tf=77.5°C are kinematic viscosity(nu=21*10**-6m**2/s),Prandtl number(Pr=0.70),Conductivity(k=0.03W/(m*K))\n", + "Tf=77.5;\n", + "nu=21*10**-6;\n", + "k=0.03;\n", + "Beta=(1/(273+Tf));#Volume expansion coefficient in k**-1)\n", + "Pr=0.70;\n", + "#g is acceleration due to gravity =9.81m/s**2\n", + "g=9.81;\n", + "#Grashoff number is given by GrD=(g*beta*(Tw-Tinf)*L**3)/(nu)**2\n", + "print\"Grashoff number is\"\n", + "GrD=(g*Beta*(Tw-Tinf)*D**3)/(nu)**2 \n", + "print\"GrD=\",GrD\n", + "#Rayleigh number is defined as RaD=GrD*Pr\n", + "print\"Rayleigh number is\"\n", + "RaD=GrD*Pr\n", + "print\"RaD=\",RaD\n", + "print\"The flow is laminar over the entire cylinder\"\n", + "#NuD is the nusselt number\n", + "print\"we use following equation to find Nusselt number NuD=(0.60+((0.387*RaD**(1/6))/(1+(0.559/Pr**(9/16)))**(8/27)))**2\"\n", + "NuD=(0.60+((0.387*RaD**(1/6))/(1+(0.559/Pr**(9/16)))**(8/27)))**2\n", + "print\"NuD=\",NuD\n", + "#hbar is the avearge heat transfer coefficient\n", + "print\"Average heat transfer coefficient in W/(m**2*K)\"\n", + "hbar=(NuD*k)/D\n", + "print\"hbar=\",hbar\n", + "#The heat loss per meter length is given by q=hbar*A*(Tw-Tinf)\n", + "print\"The heat loss per meter length in W is\"\n", + "q=hbar*A*(Tw-Tinf)\n", + "print\"q=\",q\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Ex8.8:pg-381" + ] + }, + { + "cell_type": "code", + "execution_count": 7, + "metadata": { + "collapsed": false + }, + "outputs": [ + { + "name": "stdout", + "output_type": "stream", + "text": [ + "Introduction to heat transfer by S.K.Som, Chapter 8, Example 8\n", + "Let us take first trial Tw=64°C\n", + "Grashoff number is\n", + "GrD= 226303.67232\n", + "Rayleigh number is\n", + "The flow is laminar \n", + "RaD= 941423.276851\n", + "we use following equation to find Nusselt number NuD=(0.60+((0.387*RaD**(1/6))/(1+(0.559/Pr**(9/16)))**(8/27)))**2\n", + "NuD= 0.974169\n", + "Average heat transfer coefficient in W/(m**2*K)\n", + "hbarD= 77.20289325\n", + "Hence,steady state Surface temprature in °C is\n", + "Hence we see that our guess is in excellent agreement with the calculated value\n", + "Tw= 793.068225127\n" + ] + } + ], + "source": [ + " \n", + "import math \n", + " \n", + "print\"Introduction to heat transfer by S.K.Som, Chapter 8, Example 8\"\n", + "#An electric immersion heater diameter(D)=8mm and length(L)=300mm is rated at power input,P=450W\n", + "P=450;\n", + "L=0.3;#in metre\n", + "D=0.008;#in metre\n", + "#If the heater is horizontally positioned in a large tank of stationery water at temprature,Tinf=20°C\n", + "Tinf=20;\n", + "#At steady state ,The electrical power input(P)=(Q)Heat loss from the heater\n", + "#P=Q\n", + "#Q=hbarD*(pi*D)*L*(Tw-Tinf)\n", + "#This gives Tw(surface temprature)=Tinf+(P/(hbarD*pi*D*L))\n", + "#So we need to find Average heat transfer coefficient,hbarD.\n", + "#In this problem we need to take guess of steady state surface temprature(Tw) and iterate the solution for Tw till a desired convergence is achieved.\n", + "print\"Let us take first trial Tw=64°C\"\n", + "Tw=64;\n", + "Tf=(Tw+Tinf)/2;#mean film temprature\n", + "#At this temprature of 42°C,The required properties of water kinematic viscosity(nu=6.25*10**-7m**2/s),Prandtl number(Pr=4.16),Conductivity(k=0.634W/(m*K)),Beta=4*10**-4K**-1\n", + "Beta=4*10**-4;#Volume expansion coefficient\n", + "nu=6.25*10**-7;\n", + "Pr=4.16;\n", + "k=0.634;\n", + "#g is acceleration due to gravity =9.81m/s**2\n", + "g=9.81;\n", + "#Grashoff number is given by GrD=(g*beta*(Tw-Tinf)*L**3)/(nu)**2\n", + "print\"Grashoff number is\"\n", + "GrD=(g*Beta*(Tw-Tinf)*D**3)/(nu)**2 \n", + "print\"GrD=\",GrD\n", + "#Rayleigh number is defined as RaD=GrD*Pr\n", + "print\"Rayleigh number is\"\n", + "RaD=GrD*Pr\n", + "print\"The flow is laminar \"\n", + "print\"RaD=\",RaD\n", + "#/NuD is nusselt number\n", + "#hbarD is Average heat transfer coefficient\n", + "print\"we use following equation to find Nusselt number NuD=(0.60+((0.387*RaD**(1/6))/(1+(0.559/Pr**(9/16)))**(8/27)))**2\"\n", + "NuD=(0.60+((0.387*RaD**(1/6))/(1+(0.559/Pr**(9/16)))**(8/27)))**2\n", + "print\"NuD=\",NuD\n", + "print\"Average heat transfer coefficient in W/(m**2*K)\"\n", + "hbarD=(NuD*k)/D\n", + "print\"hbarD=\",hbarD\n", + "print\"Hence,steady state Surface temprature in °C is\"\n", + "Tw=Tinf+(P/(hbarD*math.pi*D*L))\n", + "print\"Hence we see that our guess is in excellent agreement with the calculated value\"\n", + "print\"Tw=\",Tw\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n", + "\n" + ] + } + ], + "metadata": { + "kernelspec": { + "display_name": "Python 2", + "language": "python", + "name": "python2" + }, + "language_info": { + "codemirror_mode": { + "name": "ipython", + "version": 2 + }, + "file_extension": ".py", + "mimetype": "text/x-python", + "name": "python", + "nbconvert_exporter": "python", + "pygments_lexer": "ipython2", + "version": "2.7.11" + } + }, + "nbformat": 4, + "nbformat_minor": 0 +} |