{ "metadata": { "name": "", "signature": "sha256:49d323999697626f705831867b32f6c520c5287d76ed00656f7259e6db65356e" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter15:CHEMICAL REACTIONS" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex15.1:Pg-621" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#ques1\n", "#theoratical air-fuel ratio for combustion of octane\n", "#combustion equation is\n", "#C8H18 + 12.5O2 + 12.5(3.76) N2 \u2192 8 CO2 + 9H2O + 47.0N2\n", "rm=(12.5+47.0)/1;#air fuel ratio on mole basis\n", "rma=rm*28.97/114.2;#air fuel ratio on mass basis;\n", "print \"Theoratical air fuel ratio on mass basis is\",round(rma),\"kg air/kg fuel\"\n", "\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ " Theoratical air fuel ratio on mass basis is 15.0 kg air/kg fuel\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex15.6:Pg-629" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#ques6\n", "#determining heat transfer per kilomole of fuel entering combustion chamber\n", "\n", "#1-CH4\n", "#2-CO2\n", "#3-H2O\n", "#hf-standard enthalpy of given substance\n", "hf1=-74.873;#kJ\n", "hf2=-393.522;#kJ\n", "hf3=-285.830;#kJ\n", "Qcv=hf2+2*hf3-hf1;#kJ\n", "print \"Heat transfer per kilomole of fuel entering combustion chamber is\",round(Qcv,3),\"kJ\"\n", "#the answers in the book is different as they have not printed the decimals in values" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Heat transfer per kilomole of fuel entering combustion chamber is -890.309 kJ\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex15.7:Pg-631" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#ques7\n", "#calculating enthalpy of water at given pressure and temperature\n", "\n", "#1.Assuming steam to be an ideal gas with value of Cp\n", "T1=298.15;#Initial temperature in K\n", "T2=573.15;#final temperature in K\n", "T=(T1+T2)/2;#average temperature in K\n", "Cp=1.79+0.107*T/1000+0.586*(T/1000)**2-.20*(T/1000)**3;#specific heat at constant pressure in kj/kg.K\n", "M=18.015;#mass in kg\n", "dh=M*Cp*(T2-T1);#enthalpy change in kJ/kmol\n", "ho=-241.826;#enthalpy at standard temperature and pressure in kJ/mol\n", "htp1=ho+dh/1000;#enthalpy at given temp and pressure in kJ/kmol\n", "print \" 1. Enthalpy of water at given pressure and temperature using value of Cp =\",round(htp1,3),\"kJ/kmol\"\n", "\n", "#2..Assuming steam to be an ideal gas with value for dh\n", "dh=9359;#enthalpy change from table A.9 in kJ/mol\n", "htp2=ho+dh/1000;#enthalpy at given temp and pressure in kJ/kmol\n", "print \" 2. Enthalpy of water at given pressure and temperature assuming value od dh =\",round(htp2,3),\"kJ/kmol \"\n", "\n", "#3. Using steam table\n", "dh=M*(2977.5-2547.2);#enthalpy change for gases in kJ/mol\n", "htp3g=dh/1000+ho;\n", "dh=M*(2977.5-104.9);#enthalpy change for liquid in kJ/mol\n", "hl=-285.830;#standard enthalpy for liquid in kJ/kmol\n", "htp31=hl+dh/1000.0;#enthalpy at given temp and pressure in kJ/kmol\n", "print \" 3.(i) enthalpy at given temp and pressure in kJ/kmol in terms of liquid =\",round(htp31,3),\"kJ/kmol \"\n", "print \" 3.(ii) enthalpy at given temp and pressure in kJ/kmol in terms of liquid =\",round(htp3g,3),\"kJ/kmol \"\n", "#4.using generalised charts\n", "#htp=ho-(h2*-h2)+(h2*-h1*)+(h1*-h1);\n", "#h2*-h2=Z*R*Tc,\n", "#h2*-h1*=9539 kJ/mol, from part 2\n", "#h1*-h1=0 ,as ideal gas \n", "Z=0.21;#from chart\n", "R=8.3145;#gas constant in SI units\n", "Tc=647.3;#critical temperature in K\n", "htp4=ho+9539/1000-Z*R*Tc/1000;#enthalpy at given temp and pressure in kJ/kmol\n", "print \" 4. enthalpy at given temp and pressure in kJ/kmol using compressibility chart = \",round(htp4,3),\"kJ/kmol\"\n", "#the answers in book are different as they have not printed the decimals in values" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ " 1. Enthalpy of water at given pressure and temperature using value of Cp = -232.258 kJ/kmol\n", " 2. Enthalpy of water at given pressure and temperature assuming value od dh = -232.826 kJ/kmol \n", " 3.(i) enthalpy at given temp and pressure in kJ/kmol in terms of liquid = -234.08 kJ/kmol \n", " 3.(ii) enthalpy at given temp and pressure in kJ/kmol in terms of liquid = -234.074 kJ/kmol \n", " 4. enthalpy at given temp and pressure in kJ/kmol using compressibility chart = -233.956 kJ/kmol\n" ] } ], "prompt_number": 12 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex15.15:Pg-649" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#ques15\n", "#calculatng reversible elecromotive force \n", "\n", "#1-H2O\n", "#2-H2\n", "#3-O2\n", "#hf-standard enthalpy \n", "#sf-standard entropy\n", "hf1=-285.830;#kJ\n", "hf2=0;#kJ\n", "hf3=0;#kJ\n", "sf1=69.950;#kJ/K\n", "sf2=130.678;#kJ/K\n", "sf3=205.148;#kJ/K\n", "dH=2*hf1-2*hf2-hf3;#change in enthalpy in kJ\n", "dS=2*sf1-2*sf2-sf3;#change in entropy in kJ/K\n", "T=298.15;#temperature in K\n", "dG=dH-T*dS/1000;#change in gibbs free energy in kJ\n", "E=-dG*1000/(96485*4);#emf in V\n", "print\" Reversible electromotive Force =\",round(E,3),\" V\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ " Reversible electromotive Force = 1.229 V\n" ] } ], "prompt_number": 15 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex15.17:Pg-654" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#ques17\n", "#efficiency of generator and plant\n", "\n", "q=325000*(3398.3-856.0);#heat transferred to H2O/kg fuel in kJ/kg\n", "qv=26700.0*33250;#higher heating value in kJ/kg\n", "nst=q/qv*100;#efficiency of steam generator\n", "w=81000.0*3600;#net work done in kJ/kg\n", "nth=w/qv*100.0;#thermal efficiency\n", "print\" Efficiency of generator =\",round(nst,1),\"percent\\n\"\n", "print\" Thermal Efficiency =\",round(nth,1),\" percent\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ " Efficiency of generator = 93.1 percent\n", "\n", " Thermal Efficiency = 32.8 percent\n" ] } ], "prompt_number": 20 } ], "metadata": {} } ] }