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author | prashantsinalkar | 2020-04-14 10:19:27 +0530 |
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diff --git a/Basic_Engineering_Thermodynamics_by_R_Joel/10-Steam_plant.ipynb b/Basic_Engineering_Thermodynamics_by_R_Joel/10-Steam_plant.ipynb new file mode 100644 index 0000000..b888739 --- /dev/null +++ b/Basic_Engineering_Thermodynamics_by_R_Joel/10-Steam_plant.ipynb @@ -0,0 +1,695 @@ +{ +"cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Chapter 10: Steam plant" + ] + }, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 10.10: mass_and_thermal_efficiency.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 10.10');\n", +"\n", +"// aim : To determine\n", +"// (a) the mass of steam bled to each feed heater in kg/kg of supply steam\n", +"// (b) the thermal efficiency of the arrangement\n", +"\n", +"// given values\n", +"P1 = 7;// steam initial pressure, [MN/m^2]\n", +"T1 = 273+500;// steam initil temperature, [K]\n", +"P2 = 2;// pressure at stage 1, [MN/m^2]\n", +"P3 = .5;// pressure at stage 2, [MN/m^2]\n", +"P4 = .05;// condenser pressure,[MN/m^2]\n", +"SE = .82;// stage efficiency of turbine\n", +"\n", +"// solution\n", +"// from the enthalpy-entropy chart(Fig10.23) values of specific enthalpies are\n", +"h1 = 3410;// [kJ/kg]\n", +"h2_prim = 3045;// [kJ/kg]\n", +"// h1-h2=SE*(h1-h2_prim), so\n", +"h2 = h1-SE*(h1-h2_prim);// [kJ/kg]\n", +"\n", +"h3_prim = 2790;// [kJ/kg]\n", +"// h2-h3=SE*(h2-h3_prim), so\n", +"h3 = h2-SE*(h2-h3_prim);// [kJ/kg]\n", +"\n", +"h4_prim = 2450;// [kJ/kg]\n", +"// h3-h4 = SE*(h3-h4_prim), so\n", +"h4 = h3-SE*(h3-h4_prim);// [kJ/kg]\n", +"\n", +"// from steam table\n", +"// @ 2 MN/m^2\n", +"hf2 = 908.6;// [kJ/kg]\n", +"// @ .5 MN/m^2\n", +"hf3 = 640.1;// [kJ/kg] \n", +"// @ .05 MN/m^2\n", +"hf4 = 340.6;// [kJ/kg]\n", +"\n", +"// (a) \n", +"// for feed heater1\n", +"m1 = (hf2-hf3)/(h2-hf3);// mass of bled steam, [kg/kg supplied steam]\n", +"// for feed heater2\n", +"m2 = (1-m1)*(hf3-hf4)/(h3-hf4);// \n", +"mprintf('\n (a) The mass of steam bled in feed heater 1 is = %f kg/kg supply steam\n',m1);\n", +"mprintf('\n The mass of steam bled in feed heater 2 is = %f kg/kg supply steam\n',m2);\n", +"\n", +"// (b)\n", +"W = (h1-h2)+(1-m1)*(h2-h3)+(1-m1-m2)*(h3-h4);// theoretical work done, [kJ/kg]\n", +"Eb = h1-hf2;// energy input in the boiler, [kJ/kg]\n", +"TE1 = W/Eb;// thermal efficiency\n", +"mprintf('\n (b) The thermal efficiency of the arrangement is = %f percent\n',TE1*100);\n", +"\n", +"// If there is no feed heating\n", +"hf5 = hf4;\n", +"h5_prim = 2370;// [kJ/kg]\n", +"// h1-h5 = SE*(h1-h5_prim), so\n", +"h5 = h1-SE*(h1-h5_prim);// [kJ/kg]\n", +"Ei = h1-hf5;//energy input, [kJ/kg]\n", +"W = h1-h5;// theoretical work, [kJ/kg]\n", +"TE2 = W/Ei;// thermal efficiency\n", +"mprintf('\n The thermal efficiency if there is no feed heating is = %f percent\n',TE2*100);\n", +"\n", +"// End " + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 10.1: equivalent_evaporation.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 10.1');\n", +"\n", +"// aim : To determine\n", +"// the equivalent evaporation\n", +"\n", +"// Given\n", +"P = 1.4;// [MN/m^2]\n", +"m = 8;// mass of water,[kg]\n", +"T1 = 39;// entering temperature,[C]\n", +"T2 = 100;// [C]\n", +"x = .95;//dryness fraction \n", +"\n", +"// solution\n", +"hf = 830.1;// [kJ/kg]\n", +"hfg = 1957.7;// [kJ/kg]\n", +"// steam is wet so specific enthalpy of steam is\n", +"h = hf+x*hfg;// [kJ/kg]\n", +"\n", +"// at 39 C\n", +"h1 = 163.4;// [kJ/kg]\n", +"// hence\n", +"q = h-h1;// [kJ/kg]\n", +"Q = m*q;// [kJ]\n", +"\n", +"evap = Q/2256.9;// equivalent evaporation[kg steam/(kg coal)]\n", +"\n", +"mprintf('\n The equivalent evaporation, from and at 100 C is = %f kg steam/kg coal\n ',evap);\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 10.2: mass_fraction_of_enthalpy_drop_and_heat_transfer.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 10.2');\n", +"\n", +"// aim : To determine \n", +"// the mass of oil used per hour and the fraction of enthalpy drop through the turbine\n", +"// heat transfer available per kilogram of exhaust steam\n", +"\n", +"// Given values\n", +"ms_dot = 5000;// generation of steam, [kg/h]\n", +"P1 = 1.8;// generated steam pressure, [MN/m^2]\n", +"T1 = 273+325;// generated steam temperature, [K]\n", +"Tf = 273+49.4;// feed temperature, [K]\n", +"neta = .8;// efficiency of boiler plant \n", +"c = 45500;// calorific value, [kJ/kg]\n", +"P = 500;// turbine generated power, [kW]\n", +"Pt = .18;// turbine exhaust pressure, [MN/m^2]\n", +"x = .98;// dryness farction of steam\n", +"\n", +"// solution\n", +"// using steam table at 1.8 MN/m^2\n", +"hf1 = 3106;// [kJ/kg]\n", +"hg1 = 3080;// [kJ/kg]\n", +"// so\n", +"h1 = hf1-neta*(hf1-hg1);// [kJ/kg]\n", +"// again using steam table specific enthalpy of feed water is\n", +"hwf = 206.9;// [kJ/kg]\n", +"h_rais = ms_dot*(h1-hwf);// energy to raise steam, [kJ]\n", +"\n", +"h_fue = h_rais/neta;// energy from fuel per hour, [kJ]\n", +"m_oil = h_fue/c;// mass of fuel per hour, [kg]\n", +"\n", +"// from steam table at exhaust\n", +"hf = 490.7;// [kJ/kg]\n", +"hfg = 2210.8;// [kJ/kg]\n", +"// hence\n", +"h = hf+x*hfg;// [kJ/kg]\n", +"// now\n", +"h_drop = (h1-h)*ms_dot/3600;// specific enthalpy drop in turbine [kJ]\n", +"f = P/h_drop;// fraction ofenthalpy drop converted into work\n", +"// heat transfer available in exhaust is\n", +"Q = h-hwf;// [kJ/kg]\n", +"mprintf('\n The mass of oil used per hour is = %f kg\n',m_oil);\n", +"mprintf('\n The fraction of the enthalpy drop through the turbine that is converted into useful work is = %f\n',f);\n", +"mprintf('\n The heat transfer available in exhaust steam above 49.4 C is = %f kJ/kg\n',Q);\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 10.3: efficiency_equivalent_evaporation_and_coal_consumption.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 10.3');\n", +"\n", +"// aim : To determine\n", +"// (a) the thermal efficiency of the boiler\n", +"// (b) the equivalent evaporation of the boiler\n", +"// (c) the new coal consumption \n", +"\n", +"// given values\n", +"ms_dot = 5400;// steam feed rate, [kg/h]\n", +"P = 750;// steam pressure, [kN/m^2]\n", +"x = .98;// steam dryness fraction\n", +"Tf1 = 41.5;// feed water temperature, [C]\n", +"CV = 31000;// calorific value of coal used in the boiler, [kJ/kg]\n", +"mc1 = 670;// rate of burning of coal/h, [kg]\n", +"Tf2 = 100;// increased water temperature, [C]\n", +"\n", +"// solution\n", +"// (a)\n", +"SRC = ms_dot/mc1;// steam raised/kg coal, [kg]\n", +"hf = 709.3;// [kJ/kg]\n", +"hfg = 2055.5;// [kJ/kg]\n", +"h1 = hf+x*hfg;// specific enthalpy of steam raised, [kJ/kg]\n", +"// from steam table \n", +"hfw = 173.9;// specific enthalpy of feed water, [kJ/kg]\n", +"EOB = SRC*(h1-hfw)/CV;// efficiency of boiler\n", +"mprintf('\n (a) The thermal efficiency of the boiler is = %f percent\n',EOB*100);\n", +"\n", +"// (b)\n", +"he = 2256.9;// specific enthalpy of evaporation, [kJ/kg]\n", +"Ee = SRC*(h1-hfw)/he;// equivalent evaporation[kg/kg coal]\n", +"mprintf('\n (b) The equivalent evaporation of boiler is = %f kg/kg coal\n',Ee);\n", +"\n", +"// (c)\n", +"hw = 419.1;// specific enthalpy of feed water at 100 C, [kJ/kg]\n", +"Eos = ms_dot*(h1-hw);// energy of steam under new condition, [kJ/h]\n", +"neb = EOB+.05;// given condition new efficiency of boiler if 5%more than previous\n", +"Ec = Eos/neb;// energy from coal, [kJ/h]\n", +"mc2 = Ec/CV;// mass of coal used per hour in new condition, [kg]\n", +"mprintf('\n (c) Mass of coal used in new condition is = %f kg\n',mc2);\n", +"mprintf('\n The saving in coal per hour is = %f kg\n',mc1-mc2);\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 10.4: heat_transfer_and_volume.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 10.4');\n", +"\n", +"// aim : To determine the\n", +"// (a) Heat transfer in the boiler\n", +"// (b) Heat transfer in the superheater\n", +"// (c) Gas used\n", +"\n", +"// given values\n", +"P = 100;// boiler operating pressure, [bar]\n", +"Tf = 256;// feed water temperature, [C]\n", +"x = .9;// steam dryness fraction.\n", +"Th = 450;// superheater exit temperature, [C]\n", +"m = 1200;// steam generation/h, [tonne]\n", +"TE = .92;// thermal efficiency\n", +"CV = 38;// calorific value of fuel, [MJ/m^3]\n", +"\n", +"// solution\n", +"// (a)\n", +"// from steam table\n", +"hw = 1115.4;// specific enthalpy of feed water, [kJ/kg]\n", +"// for wet steam\n", +"hf = 1408;// specific enthalpy, [kJ/kg]\n", +"hg = 2727.7;// specific enthalpy, [kJ/kg]\n", +"// so\n", +"h = hf+x*(hg-hf);// total specific enthalpy of wet steam, [kJ/kg]\n", +"// hence\n", +"Qb = m*(h-hw);// heat transfer/h for wet steam, [MJ]\n", +"mprintf('\n (a) The heat transfer/h in producing wet steam in the boiler is = %f MJ\n',Qb);\n", +"\n", +"// (b)\n", +"// again from steam table\n", +"// specific enthalpy of superheated stem at given condition is,\n", +"hs = 3244;// [kJ/kg]\n", +"\n", +"Qs = m*(hs-h);// heat transfer/h in superheater, [MJ]\n", +"mprintf('\n (b) The heat transfer/h in superheater is = %f MJ\n',Qs);\n", +"\n", +"// (c)\n", +"V = (Qb+Qs)/(TE*CV);// volume of gs used/h, [m^3]\n", +"mprintf('\n (c) The volume of gas used/h is = %f m^3\n',V);\n", +"\n", +"// There is calculation mistake in the book so our answer is not matching\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 10.5: flow_rate.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 10.5');\n", +"\n", +"//aim : To determine \n", +"// the flow rate of cooling water\n", +"\n", +"//Given values\n", +"P=24;//pressure, [kN/m^2]\n", +"ms_dot=1.8;//steam condense rate,[tonne/h]\n", +"x=.98;//dryness fraction\n", +"T1=21;//entrance temperature of cooling water,[C]\n", +"T2=57;//outlet temperature of cooling water,[C]\n", +"\n", +"//solution\n", +"//at 24 kN/m^2, for steam\n", +"hfg=2616.8;//[kJ/kg]\n", +"hf1=268.2;//[kJ/kg]\n", +"//hence\n", +"h1=hf1+x*(hfg-hf1);//[kJ/kg]\n", +"\n", +"//for cooling water\n", +"hf3=238.6;//[kJ/kg]\n", +"hf2=88.1;//[kJ/kg]\n", +"\n", +"//using equation [3]\n", +"//ms_dot*(hf3-hf2)=mw_dot*(h1-hf1),so\n", +"mw_dot=ms_dot*(h1-hf1)/(hf3-hf2);//[tonne/h]\n", +"disp('tonne/h',mw_dot,'The flow rate of the cooling water is =')\n", +"\n", +"//End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 10.6: energy_supplied_dryness_fraction_and_Rankine_efficiency.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 10.6');\n", +"\n", +"// aim : To determine\n", +"// (a) the energy supplied in the boiler\n", +"// (b) the dryness fraction of the steam entering the condenser\n", +"// (c) the rankine efficiency\n", +"\n", +"// given values\n", +"P1 = 3.5;// steam entering pressure, [MN/m^2]\n", +"T1 = 273+350;// entering temperature, [K]\n", +"P2 = 10;//steam exhaust pressure, [kN/m^2]\n", +"\n", +"// solution\n", +"// (a)\n", +"// from steam table, at P1 is,\n", +"hf1 = 3139;// [kJ/kg]\n", +"hg1 = 3095;// [kJ/kg]\n", +"h1 = hf1-1.5/2*(hf1-hg1);\n", +"// at Point 3\n", +"h3 = 191.8;// [kJ/kg]\n", +"Es = h1-h3;// energy supplied, [kJ/kg]\n", +"mprintf('\n (a) The energy supplied in boiler/kg steam is = %f kJ/kg\n',Es);\n", +"\n", +"// (b)\n", +"// at P1\n", +"sf1 = 6.960;// [kJ/kg K]\n", +"sg1 = 6.587;// [kJ/kg K]\n", +"s1 = sf1-1.5/2*(sf1-sg1);// [kJ/kg K]\n", +"// at P2\n", +"sf2 = .649;// [kJ/kg K] \n", +" sg2 = 8.151;// [kJ/kg K]\n", +" // s2=sf2+x2(sg2-sf2)\n", +" // theoretically expansion through turbine is isentropic so s1=s2\n", +" // hence\n", +" s2 = s1;\n", +" x2 = (s2-sf2)/(sg2-sf2);// dryness fraction\n", +" mprintf('\n (b) The dryness fraction of steam entering the condenser is = %f \n',x2);\n", +" \n", +" // (c)\n", +" // at point 2\n", +" hf2 = 191.8;// [kJ/kg]\n", +" hfg2 = 2392.9;// [kJ/kg]\n", +" h2 = hf2+x2*hfg2;// [kJ/kg]\n", +" Re = (h1-h2)/(h1-h3);// rankine efficiency\n", +" mprintf('\n (c) The Rankine efficiency is = %f percent\n',Re*100);\n", +" \n", +" // End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 10.7: Rankine_efficiency_and_specific_work_done.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 10.7');\n", +"\n", +"// aim : To determine\n", +"// the specific work done and compare this with that obtained when determining the rankine effficiency\n", +"\n", +"// given values\n", +"P1 = 1000;// steam entering pressure, [kN/m^2]\n", +"x1 = .97;// steam entering dryness fraction\n", +"P2 = 15;//steam exhaust pressure, [kN/m^2]\n", +"n = 1.135;// polytropic index\n", +"\n", +"// solution\n", +"// (a)\n", +"// from steam table, at P1 is\n", +"hf1 = 762.6;// [kJ/kg]\n", +"hfg1 = 2013.6;// [kJ/kg]\n", +"h1 = hf1+hfg1; // [kJ/kg]\n", +"\n", +"sf1 = 2.138;// [kJ/kg K]\n", +"sg1 = 6.583;// [kJ/kg K]\n", +"s1 = sf1+x1*(sg1-sf1);// [kJ/kg K]\n", +"\n", +"// at P2\n", +"sf2 = .755;// [kJ/kg K] \n", +" sg2 = 8.009;// [kJ/kg K]\n", +"// s2 = sf2+x2(sg2-sf2)\n", +"// since expansion through turbine is isentropic so s1=s2\n", +" // hence\n", +" s2 = s1;\n", +" x2 = (s2-sf2)/(sg2-sf2);// dryness fraction\n", +" \n", +" // at point 2\n", +" hf2 = 226.0;// [kJ/kg]\n", +" hfg2 = 2373.2;// [kJ/kg]\n", +" h2 = hf2+x2*hfg2;// [kJ/kg]\n", +" \n", +"// at Point 3\n", +"h3 = 226.0;// [kJ/kg]\n", +"\n", +"// (a)\n", +" Re = (h1-h2)/(h1-h3);// rankine efficiency\n", +" mprintf('\n (a) The Rankine efficiency is = %f percent\n',Re*100);\n", +" \n", +"// (b)\n", +"vg1 = .1943;// specific volume at P1, [m^3/kg]\n", +"vg2 = 10.02;// specific volume at P2, [m^3/kg]\n", +"V1 = x1*vg1;// [m^3/kg]\n", +"V2 = x2*vg2;// [m^3/kg]\n", +"\n", +"W1 = n/(n-1)*(P1*V1-P2*V2);// specific work done, [kJ/kg]\n", +"\n", +"// from rankine cycle\n", +"W2 = h1-h2;// [kJ/kg]\n", +"mprintf('\n (b) The specific work done is = %f kJ/kg\n',W1);\n", +"mprintf('\n The specific work done (from rankine) is = %f kJ/kg\n',W2);\n", +"\n", +"// there is calculation mistake in the book so our answer is not matching\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 10.8: Rankine_efficiency_steam_consumption_and_Carnot_efficiency.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 10.8');\n", +"\n", +"// aim : To determine\n", +"// (a) the rankine fficiency\n", +"// (b) the specific steam consumption\n", +"// (c) the carnot efficiency of the cycle\n", +"\n", +"// given values\n", +"P1 = 1100;// steam entering pressure, [kN/m^2]\n", +"T1 = 273+250;// steam entering temperature, [K]\n", +"P2 = 280;// pressure at point 2, [kN/m^2]\n", +"P3 = 35;// pressure at point 3, [kN/m^2]\n", +"\n", +"// solution\n", +"// (a)\n", +"// from steam table, at P1 and T1 is\n", +"hf1 = 2943;// [kJ/kg]\n", +"hg1 = 2902;// [kJ/kg]\n", +"h1 = hf1-.1*(hf1-hg1); // [kJ/kg]\n", +"\n", +"sf1 = 6.926;// [kJ/kg K]\n", +"sg1 = 6.545;// [kJ/kg K]\n", +"s1 = sf1-.1*(sf1-sg1);// [kJ/kg K]\n", +"\n", +"// at P2\n", +"sf2 = 1.647;// [kJ/kg K] \n", +" sg2 = 7.014;// [kJ/kg K]\n", +"// s2=sf2+x2(sg2-sf2)\n", +"// since expansion through turbine is isentropic so s1=s2\n", +" // hence\n", +" s2 = s1;\n", +" x2 = (s2-sf2)/(sg2-sf2);// dryness fraction\n", +" \n", +" // at point 2\n", +" hf2 = 551.4;// [kJ/kg]\n", +" hfg2 = 2170.1;// [kJ/kg]\n", +" h2 = hf2+x2*hfg2;// [kJ/kg]\n", +" vg2 = .646;// [m^3/kg]\n", +" v2 = x2*vg2;// [m^3/kg]\n", +" \n", +" // by Fig10.20.\n", +" A6125 = h1-h2;// area of 6125, [kJ/kg]\n", +" A5234 = v2*(P2-P3);// area 5234, [kJ/kg]\n", +" W = A6125+A5234;// work done \n", +" hf = 304.3;// specific enthalpy of water at condenser pressuer, [kJ/kg]\n", +" ER = h1-hf;// energy received, [kJ/kg]\n", +" Re = W/ER;// rankine efficiency\n", +" mprintf('\n (a) The rankine efficiency is = %f percent\n',Re*100);\n", +" \n", +" // (b)\n", +" kWh = 3600;// [kJ]\n", +" SSC = kWh/W;// specific steam consumption, [kJ/kWh]\n", +" mprintf('\n (b) The specific steam consumption is = %f kJ/kWh\n',SSC);\n", +" \n", +" // (c)\n", +" // from steam table \n", +"T3 = 273+72.7;// temperature at point 3\n", +"CE = (T1-T3)/T1;// carnot efficiency\n", +"mprintf('\n (c) The carnot efficiency of the cycle is = %f percent\n',CE*100);\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 10.9: power_and_thermal_efficiency.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 10.9');\n", +"\n", +"// aim : To determine\n", +"// (a) the theoretical power of steam passing through the turbine\n", +"// (b) the thermal efficiency of the cycle\n", +"// (c) the thermal efficiency of the cycle assuming there is no reheat\n", +"\n", +"// given values\n", +"P1 = 6;// initial pressure, [MN/m^2]\n", +"T1 = 450;// initial temperature, [C]\n", +"P2 = 1;// pressure at stage 1, [MN/m^2]\n", +"P3 = 1;// pressure at stage 2, [MN/m^2]\n", +"T3 = 370;// temperature, [C]\n", +"P4 = .02;// pressure at stage 3, [MN/m^2]\n", +"P5 = .02;// pressure at stage 4, [MN/m^2]\n", +"T5 = 320;// temperature, [C]\n", +"P6 = .02;// pressure at stage 5, [MN/m^2]\n", +"P7 = .02;// final pressure , [MN/m^2]\n", +"\n", +"// solution\n", +"// (a) \n", +"// using Fig 10.21\n", +"h1 = 3305;// specific enthalpy, [kJ/kg]\n", +"h2 = 2850;// specific enthalpy, [kJ/kg]\n", +"h3 = 3202;// specific enthalpy, [kJ/kg]\n", +"h4 = 2810;// specific enthalpy, [kJ/kg]\n", +"h5 = 3115;// specific enthalpy, [kJ/kg]\n", +"h6 = 2630;// specific enthalpy, [kJ/kg]\n", +"h7 = 2215;// specific enthalpy, [kJ/kg]\n", +"W = (h1-h2)+(h3-h4)+(h5-h6);// specific work through the turbine, [kJ/kg]\n", +"mprintf('\n (a) The theoretical power/kg steam/s is = %f kW\n',W);\n", +"\n", +"// (b)\n", +"// from steam table\n", +"hf6 = 251.5;// [kJ/kg]\n", +"\n", +"TE1 = ((h1-h2)+(h3-h4)+(h5-h6))/((h1-hf6)+(h3-h2)+(h5-h4));// thermal efficiency\n", +"mprintf('\n (b) The thermal efficiency of the cycle is = %f percent\n',TE1*100);\n", +"\n", +"// (c)\n", +"// if there is no heat\n", +"hf7 = hf6;\n", +"TE2 = (h1-h7)/(h1-hf7);// thermal efficiency\n", +"mprintf('\n (c) The thermal efficiency of the cycle if there is no heat is = %f percent\n',TE2*100);\n", +"\n", +"// End" + ] + } +], +"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 +} |