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diff --git a/Introduction_to_Heat_Transfer_by_S._K._Som/Chapter12.ipynb b/Introduction_to_Heat_Transfer_by_S._K._Som/Chapter12.ipynb new file mode 100644 index 00000000..6fafa3fd --- /dev/null +++ b/Introduction_to_Heat_Transfer_by_S._K._Som/Chapter12.ipynb @@ -0,0 +1,268 @@ +{ + "cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Chapter 12:Principles of mass transfer" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Ex12.1:pg-496" + ] + }, + { + "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 12, Example 1\n", + "The flow area is given by A=(pi*di**2)/4 in m**2\n", + "3e-05\n", + "The molar concentration of mixture which is constant throughout is given by c=p/(R*T)\n", + "0.04079\n", + "Nhe=Nair=(A*c*Db*(Yao-yal))/L in kmol/sec\n", + "mass flow rate of helium is given by m=Mhe*Nhe in kg/sec \n", + "1.7e-11\n", + "mass flow rate of air is given by m=Mair*Nair in kg/sec \n", + "1.2e-10\n" + ] + } + ], + "source": [ + "\n", + "import math\n", + "\n", + "print \"Introduction to heat transfer by S.K.Som, Chapter 12, Example 1\"\n", + "#The pressure in the pipeline that transports helium gas at a rate of 4kg/s is maintained at pressure(p)=1 atm or 101*10**3 pascal.\n", + "#The internal daimeter of tube is (di)=6mm or .006m\n", + "#The temprature of both air and helium is (T)=25°C or 298 K.\n", + "#The diffusion coefficient of helium in air at normal atmosphere is(Dab)=7.20*10**-5 m**2/s\n", + "#The venting tube extends to a length(L)=20m in the atmosphere.\n", + "di=.006;\n", + "print \"The flow area is given by A=(pi*di**2)/4 in m**2\"\n", + "A=(math.pi*di**2)/4\n", + "print round(A,5)\n", + "p=101*10**3;\n", + "R=8.31*10**3;#gas constant\n", + "T=298;\n", + "Dab=7.20*10**-5;\n", + "L=20;\n", + "#c is the molar concentration\n", + "print \"The molar concentration of mixture which is constant throughout is given by c=p/(R*T)\"\n", + "c=p/(R*T)\n", + "print round(c,5)\n", + "#helium has been considered as species A so (helium mole fraction at the bottom of the tube)is Yao=1 and (helium mole fraction at the bottom of the tube)is Yal=0\n", + "Yal=0;\n", + "Yao=1;\n", + "#Nhe and Nair are molar rate of helium and air respectively\n", + "print \"Nhe=Nair=(A*c*Db*(Yao-yal))/L in kmol/sec\"\n", + "Nair=(A*c*Dab*(Yao-Yal))/L\n", + "Nhe=Nair;\n", + "#Molecular weights of air and helium are 29kg/kmol and 4 kg/kmol respectively.\n", + "Mhe=4;\n", + "Mair=29;\n", + "#mass flow rate of helium is mhe\n", + "print \"mass flow rate of helium is given by m=Mhe*Nhe in kg/sec \"\n", + "mhe=Mhe*Nhe\n", + "print round(mhe,12)\n", + "#mass flow rate of air is mair\n", + "print \"mass flow rate of air is given by m=Mair*Nair in kg/sec \"\n", + "mair=Mair*Nair\n", + "print round(mair,11)\n" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Ex12.2:pg-500" + ] + }, + { + "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 12, Example 2\n", + "The film temperature is given by Tf=(T+Tw)/2 in °C \n", + "30.0\n", + "The density of water at bulb surface is given by rhos=(Ps*M)/(R*Ts) in kg/m**3 \n", + "0.0173\n", + "The concentration of water vapour at free stream is rhoinf=rhos-(hheat/hmass)*((Tinf-Ts)/hfg) in kg/m**3 \n", + "0.00784\n", + "The relative humidity is given by rehu=(rhoinf/rhosteam)*100 in percentage \n", + "15.38028\n" + ] + } + ], + "source": [ + "\n", + "import math\n", + "print \"Introduction to heat transfer by S.K.Som, Chapter 12, Example 2\"\n", + "#The temprature of atmospheric air (T)=40°C which flows over a wet bulb thermometer.\n", + "#The reading of wet bulb thermometer which is called the wet bulb temprature is (Tw)=20°C\n", + "T=40;\n", + "Tw=20.0;\n", + "#Tf is the film temprature\n", + "print \"The film temperature is given by Tf=(T+Tw)/2 in °C \"\n", + "Tf=(T+Tw)/2\n", + "print round(Tf,5)\n", + "Tinf=T;#surrounding temprature\n", + "#The properties of air at film temprature are density(rho=1.13kg/m**3),specific heat(cp=1.007kJ/(kg*K)),Thermal diffusivity(alpha=0.241*10**-4m**2/s)\n", + "#The diffusivity Dab=0.26*10**-4 m**2/s\n", + "#The enthalpy of vaporisation of water at 20°C is hfg=2407kJ/kg or 2407*10**3 J/kg\n", + "#The partial pressure of water vapour is the saturation pressure corresponding to 20°C so from steam table Ps=2.34kPa or 2.34*10**3 Pa.\n", + "rho=1.13;\n", + "cp=1.007*10**3;\n", + "alpha=0.241*10**-4;\n", + "Dab=0.26*10**-4;\n", + "hfg=2407*10**3;\n", + "Ps=2.34*10**3;\n", + "#The temprature at bulb surface Ts=20°C or 293K\n", + "Ts=Tw+273;#in kelvin\n", + "R=8.31*10**3;#gas constant\n", + "#The molecular weight of water is M=18\n", + "M=18;\n", + "#The density of water at bulb surface is rhos\n", + "print \"The density of water at bulb surface is given by rhos=(Ps*M)/(R*Ts) in kg/m**3 \"\n", + "rhos=(Ps*M)/(R*Ts)\n", + "print round(rhos,5)\n", + "#Let X=hheat/hmass=rho*cp*(alpha/Dab)**(2/3).\n", + "X=rho*cp*(alpha/Dab)**(2/3);\n", + "#At steady atate (Rate of heat transfer from air to wet cover of thermometer bulb)=(Heat removed by evaporation of water from the wet cover of thermometer bulb)\n", + "#hheat*(Tinf-Ts)=hmass*(rhos-rhoinf)*hfg\n", + "#Rearranging above we get rhoinf=rhos-(hheat/hmass)*((Tinf-Ts)/hfg)\n", + "#The concentration of water vapour at free stream is rhoinf\n", + "print \"The concentration of water vapour at free stream is rhoinf=rhos-(hheat/hmass)*((Tinf-Ts)/hfg) in kg/m**3 \"\n", + "rhoinf=rhos-((X)*((Tinf-Tw)/hfg))\n", + "print round(rhoinf,5)\n", + "#The mass concentration of saturated water vapour(rhosteam) at 40°C(as found from steam table) is .051 kg/m**3\n", + "rhosteam=.051;\n", + "#The relative humidity is (rehu)\n", + "print \"The relative humidity is given by rehu=(rhoinf/rhosteam)*100 in percentage \"\n", + "rehu=(rhoinf/rhosteam)*100\n", + "print round(rehu,5)" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Ex12.3:pg-503" + ] + }, + { + "cell_type": "code", + "execution_count": 20, + "metadata": { + "collapsed": false + }, + "outputs": [ + { + "name": "stdout", + "output_type": "stream", + "text": [ + "Introduction to heat transfer by S.K.Som, Chapter 12, Example 3\n", + "The mole fraction of water vapour at the interface is given by Yao=pvapour/p\n", + "0.03963\n", + "The total molecular concentration (c) through the tube remains constant is given by c=p/(R*T) in kmol/m**3\n", + "0.03286\n", + "The cross sectional area of the tube is given by A=(pi*(di*10**-3)**2)/4 in m**2\n", + "0.00096\n", + "The molar flow rate of water vapour is given by N=mdot/M in kmol/s\n", + "1e-10\n", + "The diffusion coefficient of water vapour is Dab=(N*L)/(c*A*ln[(1-Yal)/(1-Yao)]) in m/s\n", + "3e-05\n" + ] + } + ], + "source": [ + "\n", + "import math\n", + "\n", + "print \"Introduction to heat transfer by S.K.Som, Chapter 12, Example 3\"\n", + "#The diameter of tube is (di)=35mm which measures binary diffusion coefficient of water vapour in air at temprature,T=20°C or 293 K.\n", + "#The measurement is done at height of 1500 m where the atmospheric pressure is (p)=80kPa.\n", + "p=80;\n", + "T=293.0;\n", + "#The distance from the water surface to the open end of the tube is L=500 mm or 0.5m.\n", + "L=.5;\n", + "#After t=12 days of continuous operation at constant pressure and temprature the amount of water evaporated was measured to be m= 1.2*10**-3kg.\n", + "m= 1.2*10**-3;\n", + "#From the steam table pvapour=3.17kPa\n", + "pvapour=3.17;#partial pressure of vapour\n", + "#Yao is the mole fraction of water vapour at the interface\n", + "print \"The mole fraction of water vapour at the interface is given by Yao=pvapour/p\"\n", + "Yao=pvapour/p\n", + "print round(Yao,5)\n", + "#The mole fraction of water vapour at the top end of the tube is Yal=0\n", + "Yal=0;\n", + "R=8.31*10**3;#gas constant\n", + "#The total molecular concentration is (c)\n", + "print \"The total molecular concentration (c) through the tube remains constant is given by c=p/(R*T) in kmol/m**3\"\n", + "c=(p*10**3)/(R*T)\n", + "print round(c,5)\n", + "di=35;\n", + "#A is the cross sectional area of the tube\n", + "print \"The cross sectional area of the tube is given by A=(pi*(di*10**-3)**2)/4 in m**2\"\n", + "A=(math.pi*(di*10**-3)**2)/4\n", + "print round(A,5)\n", + "#The molecular weight of wate is M=18\n", + "M=18;\n", + "#The mass flow rate is given by mdot=(m/(12*24*3600))\n", + "mdot=(m/(12*24*3600));\n", + "#N is the molar flow rate of water vapour\n", + "print \"The molar flow rate of water vapour is given by N=mdot/M in kmol/s\"\n", + "N=mdot/M\n", + "print round(N,10)\n", + "#The molar flow rate of water vapour can also be written as N=(c*Dab*A*ln[(1-Yal)/(1-Yao)])/L\n", + "#The diffusion coefficient of water vapour is Dab=(N*L)/(c*A*ln[(1-Yal)/(1-Yao)])\n", + "#let us take X=math.log10((1-Yal)/(1-Yao)) and Y=math.log10(2.7182)\n", + "X=math.log10((1-Yal)/(1-Yao));\n", + "Y=math.log10(2.7182);\n", + "#ln[(1-Yal)/(1-Yao)] is given by\n", + "ln=X/Y;\n", + "print \"The diffusion coefficient of water vapour is Dab=(N*L)/(c*A*ln[(1-Yal)/(1-Yao)]) in m/s\"\n", + "Dab=(N*L)/(c*A*ln)\n", + "print round(Dab,5)" + ] + } + ], + "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 +} |