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author | Prashant S | 2020-04-14 10:25:32 +0530 |
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committer | GitHub | 2020-04-14 10:25:32 +0530 |
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tree | 2b1df110e24ff0174830d7f825f43ff1c134d1af /Basic_Engineering_Thermodynamics_by_R_Joel/4-Steam_and_two_phase_systems.ipynb | |
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diff --git a/Basic_Engineering_Thermodynamics_by_R_Joel/4-Steam_and_two_phase_systems.ipynb b/Basic_Engineering_Thermodynamics_by_R_Joel/4-Steam_and_two_phase_systems.ipynb new file mode 100644 index 0000000..aa80cfc --- /dev/null +++ b/Basic_Engineering_Thermodynamics_by_R_Joel/4-Steam_and_two_phase_systems.ipynb @@ -0,0 +1,1096 @@ +{ +"cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Chapter 4: Steam and two phase systems" + ] + }, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.10: mass_of_steam_and_water.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example .10');\n", +"\n", +"// aim : To determine\n", +"// (a) the mass of steam entering the heater\n", +"// (b) the mass of water entering the heater\n", +"\n", +"// Given values\n", +"x = .95;// Dryness fraction\n", +"P = .7;// pressure,[MN/m^2]\n", +"d = 25;// internal diameter of heater,[mm]\n", +"C = 12; // steam velocity in the pipe,[m/s]\n", +"\n", +"// solution\n", +"// from steam table at .7 MN/m^2 pressure\n", +"hf = 697.1;// [kJ/kg]\n", +"hfg = 2064.9;// [kJ/kg]\n", +"hg = 2762.0; // [kJ/kg]\n", +"vg = .273; // [m^3/kg]\n", +"\n", +"// (a)\n", +"v = x*vg; // [m^3/kg]\n", +"ms_dot = %pi*(d*10^-3)^2*C*3600/(4*v);// mass of steam entering, [kg/h]\n", +"mprintf('\n (a) The mass of steam entering the heater is = %f kg/h \n',ms_dot);\n", +"\n", +"// (b)\n", +"h = hf+x*hfg;// specific enthalpy of steam entering heater,[kJ/kg]\n", +"// again from steam tables\n", +"hf1 = 376.8;// [kJ/kg] at 90 C\n", +"hf2 = 79.8;// [kJ/kg] at 19 C\n", +"\n", +"// using energy balance,mw_dot*(hf1-hf2)=ms_dot*(h-hf1)\n", +"mw_dot = ms_dot*(h-hf1)/(hf1-hf2);// mass of water entering to heater,[kg/h]\n", +"\n", +"mprintf('\n (b) The mass of water entering the heater is = %f kg/h \n',mw_dot);\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.11: change_of_internal_energy.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 4.11');\n", +"\n", +"// aim: To determine\n", +"// the change of internal energy\n", +"\n", +"// Given values\n", +"m = 1.5;// mass of steam,[kg]\n", +"P1 = 1;// initial pressure, [MN/m^2]\n", +"t = 225;// temperature, [C]\n", +"P2 = .28;// final pressure, [MN/m^2]\n", +"x = .9;// dryness fraction of steam at P2\n", +"\n", +"// solution\n", +"\n", +"// from steam table at P1\n", +"h1 = 2886;// [kJ/kg]\n", +"v1 = .2198; // [m^3/kg]\n", +"// hence\n", +"u1 = h1-P1*v1*10^3;// internal energy [kJ/kg]\n", +"\n", +"// at P2\n", +"hf2 = 551.4;// [kJ/kg]\n", +"hfg2 = 2170.1;// [kJ/kg]\n", +"vg2 = .646; // [m^3/kg]\n", +"// so\n", +"h2 = hf2+x*hfg2;// [kj/kg]\n", +"v2 = x*vg2;// [m^3/kg]\n", +"\n", +"// now\n", +"u2 = h2-P2*v2*10^3;// [kJ/kg]\n", +"\n", +"// hence change in specific internal energy is\n", +"del_u = u2-u1;// [kJ/kg]\n", +"\n", +"del_u = m*del_u;// [kJ];\n", +"mprintf('\n The change in internal energy is = %f kJ \n',del_u);\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.12: dryness_fraction.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 4.12');\n", +"\n", +"// aim : To determine \n", +"// the dryness fraction of steam after throttling\n", +"\n", +"// given values\n", +"P1 = 1.4;// pressure before throttling, [MN/m^2]\n", +"x1 = .7;// dryness fraction before throttling\n", +"P2 = .11;// pressure after throttling, [MN/m^2]\n", +"\n", +"// solution\n", +"// from steam table\n", +"hf1 = 830.1;// [kJ/kg]\n", +"hfg1 = 1957.7;// [kJ/kg]\n", +"h1 = hf1 + x1*hfg1; // [kJ/kg]\n", +"\n", +"hf2 = 428.8;// [kJ/kg]\n", +"hfg2 = 2250.8;// [kJ/kg]\n", +"\n", +"// now for throttling,\n", +"// hf1+x1*hfg1=hf2+x2*hfg2; where x2 is dryness fraction after throttling\n", +"\n", +"x2=(h1-hf2)/hfg2; // final dryness fraction\n", +"\n", +"mprintf('\n Dryness fraction of steam after throttling is = %f \n',x2);\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.13: condition_of_steam_and_internal_diameter.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 4.13');\n", +"\n", +"// aim : To determine \n", +"// the dryness fraction of steam \n", +"// and the internal diameter of the pipe\n", +"\n", +"// Given values\n", +"\n", +"// steam1\n", +"P1 = 2;// pressure before throttling, [MN/m^2]\n", +"t = 300;// temperature,[C]\n", +"ms1_dot = 2;// steam flow rate, [kg/s]\n", +"P2 = 800;// pressure after throttling, [kN/m^2]\n", +"\n", +"// steam2\n", +"P = 800;// pressure, [N/m^2]\n", +"x2 = .9;// dryness fraction\n", +"ms2_dot = 5; // [kg/s]\n", +"\n", +"// solution\n", +"// (a)\n", +"// from steam table specific enthalpy of steam1 before throttling is\n", +"hf1 = 3025;// [kJ/kg]\n", +"// for throttling process specific enthalpy will same so final specific enthalpy of steam1 is\n", +"hf2 = hf1;\n", +"// hence\n", +"h1 = ms1_dot*hf2;// [kJ/s]\n", +"\n", +"// calculation of specific enthalpy of steam2\n", +"hf2 = 720.9;// [kJ/kg]\n", +"hfg2 = 2046.5;// [kJ/kg]\n", +"// hence\n", +"h2 = hf2+x2*hfg2;// specific enthalpy, [kJ/kg]\n", +"h2 = ms2_dot*h2;// total enthalpy, [kJ/s]\n", +"\n", +"// after mixing\n", +"m_dot = ms1_dot+ms2_dot;// total mass of mixture,[kg/s]\n", +"h = h1+h2;// Total enthalpy of the mixture,[kJ/s]\n", +"h = h/7;// [kJ/kg]\n", +"\n", +"// At pressure 800 N/m^2 \n", +"hf = 720.9;// [kJ/kg]\n", +"hfg = 2046.5;// [kJ/kg]\n", +"// so total enthalpy is,hf+x*hfg, where x is dryness fraction of mixture and which is equal to h\n", +"// hence\n", +"x = (h-hf)/hfg;// dryness fraction after mixing\n", +"mprintf('\n (a) The condition of the resulting mixture is dry with dryness fraction = %f \n',x);\n", +"\n", +"// (b)\n", +"// Given\n", +"C = 15;// velocity, [m/s]\n", +"// from steam table\n", +"v = .1255;// [m^/kg]\n", +"A = ms1_dot*v/C;// area, [m^2]\n", +"// using ms1_dot = A*C/v, where A is cross section area in m^2 and\n", +"// A = %pi*d^2/4, where d is diameter of the pipe \n", +"\n", +"// calculation of d\n", +"d = sqrt(4*A/%pi); // diameter, [m]\n", +"\n", +"mprintf('\n (b) The internal diameter of the pipe is = %f mm \n',d*1000);\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.14: dryness_fraction.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 4.14');\n", +"\n", +"// aim : To estimate \n", +"// the dryness fraction\n", +"\n", +"// Given values\n", +"M = 1.8;// mass of condensate, [kg]\n", +"m = .2;// water collected, [kg]\n", +"\n", +"// solution\n", +"x = M/(M+m);// formula for calculation of dryness fraction using seprating calorimeter\n", +"\n", +"mprintf(' \n The dryness fraction of the steam entering seprating calorimeter is = %f \n',x);\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.15: dryness_fraction.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 4.15');\n", +"\n", +"// aim : To determine\n", +"// the dryness fraction of the steam at 2.2 MN/m^2\n", +"\n", +"// Given values\n", +"P1 = 2.2;// [MN/m^2]\n", +"P2 = .13;// [MN/m^2]\n", +"t2 = 112;// [C]\n", +"tf2 = 150;// temperature, [C]\n", +"\n", +"// solution\n", +"// from steam table, at 2.2 MN/m^2\n", +"// saturated steam at 2 MN/m^2 Pressure\n", +"hf1 = 931;// [kJ/kg]\n", +"hfg1 = 1870;// [kJ/kg]\n", +"hg1 = 2801;// [kJ/kg]\n", +"\n", +"// for superheated steam\n", +"// at .1 MN/m^2\n", +"hg2 = 2675;// [kJ/kg]\n", +"hg2_150 = 2777;// specific enthalpy at 150 C, [kJ/kg]\n", +"tf2 = 99.6;// saturation temperature, [C]\n", +"\n", +"// at .5 MN/m^2\n", +"hg3 = 2693;// [kJ/kg]\n", +"hg3_150 = 2773;// specific enthalpy at 150 C, [kJ/kg]\n", +"tf3 = 111.4;// saturation temperature, [C]\n", +"\n", +"Table_P_h1 = [[.1,.5];[hg2,hg3]];// where, P in MN/m^2 and h in [kJ/kg]\n", +"hg = interpln(Table_P_h1,.13);// specific entahlpy at .13 MN/m^2, [kJ/kg]\n", +"\n", +"Table_P_h2 = [[.1,.5];[hg2_150,hg3_150]];// where, P in MN/m^2 and h in [kJ/kg]\n", +"hg_150 = interpln(Table_P_h2,.13);// specific entahlpy at .13 MN/m^2 and 150 C, [kJ/kg]\n", +"\n", +"Table_P_tf = [[.1,.5];[tf2,tf3]];// where, P in MN/m^2 and h in [kJ/kg]\n", +"tf = interpln(Table_P_tf,.13);// saturation temperature, [C]\n", +"\n", +"// hence\n", +"h2 = hg+(hg_150-hg)/(t2-tf)/(tf2-tf);// specific enthalpy at .13 MN/m^2 and 112 C, [kJ/kg]\n", +"\n", +"// now since process is throttling so h2=h1\n", +"// and h1 = hf1+x1*hfg1, so\n", +"x1 = (h2-hf1)/hfg1;// dryness fraction\n", +"mprintf(' \n The dryness fraction of steam is = %f \n',x1);\n", +"\n", +"// There is a calculation mistake in book so answer is not matching\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.16: minimum_dryness_fraction.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 4.16');\n", +"\n", +"// aim : To determine \n", +"// the minimum dryness fraction of steam\n", +"\n", +"// Given values\n", +"P1 = 1.8;// testing pressure,[MN/m^2]\n", +"P2 = .11;// pressure after throttling,[MN/m^2]\n", +"\n", +"// solution\n", +"// from steam table\n", +"// at .11 MN/m^2 steam is completely dry and specific enthalpy is\n", +"hg = 2680;// [kJ/kg]\n", +"\n", +"// before throttling steam is wet, so specific enthalpy is=hf+x*hfg, where x is dryness fraction\n", +"// from steam table\n", +"hf = 885;// [kJ/kg]\n", +"hfg = 1912;// [kJ/kg]\n", +"\n", +"// now for throttling process,specific enthalpy will same before and after\n", +"// hence\n", +"x = (hg-hf)/hfg;\n", +"mprintf('\n The minimum dryness fraction of steam is x = %f \n',x);\n", +"\n", +"// End\n", +"" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.17: mass_dryness_fraction_and_heat_transfer.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 4.17');\n", +"\n", +"// aim : To determine the\n", +"// (a) mass of steam in the vessel\n", +"// (b) final dryness of the steam\n", +"// (c) amount of heat transferrred during the cooling process\n", +"\n", +"// Given values\n", +"V1 = .8;// [m^3]\n", +"P1 = 360;// [kN/m^2]\n", +"P2 = 200;// [kN/m^2]\n", +"\n", +"// solution\n", +"\n", +"// (a)\n", +"// at 360 kN/m^2\n", +"vg1 = .510;// [m^3]\n", +"m = V1/vg1;// mass of steam,[kg]\n", +"mprintf('\n (a) The mass of steam in the vessel is = %f kg\n',m);\n", +"\n", +"// (b)\n", +"// at 200 kN/m^2\n", +"vg2 = .885;// [m^3/kg]\n", +"// the volume remains constant so\n", +"x = vg1/vg2;// final dryness fraction\n", +"mprintf('\n (b) The final dryness fraction of the steam is = %f \n',x);\n", +"\n", +"// (c)\n", +"// at 360 kN/m^2\n", +"h1 = 2732.9;// [kJ/kg]\n", +"// hence\n", +"u1 = h1-P1*vg1;// [kJ/kg]\n", +"\n", +"// at 200 kN/m^2\n", +"hf = 504.7;// [kJ/kg]\n", +"hfg=2201.6;//[kJ/kg]\n", +"// hence\n", +"h2 = hf+x*hfg;// [kJ/kg]\n", +"// now\n", +"u2 = h2-P2*vg1;// [kJ/kg]\n", +"// so\n", +"del_u = u2-u1;// [kJ/kg]\n", +"// from the first law of thermodynamics del_U+W=Q, \n", +"W = 0;// because volume is constant\n", +"del_U = m*del_u;// [kJ]\n", +"// hence\n", +"Q = del_U;// [kJ]\n", +"mprintf('\n (c) The amount of heat transferred during cooling process is = %f kJ \n',Q);\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.18: specific_heat.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 4.18');\n", +"\n", +"// aim : To determine\n", +"// the heat received by the steam per kilogram\n", +"\n", +"// Given values\n", +"// initial\n", +"P1 = 4;// pressure, [MN/m^2]\n", +"x1 = .95; // dryness fraction\n", +"\n", +"// final\n", +"t2 = 350;// temperature,[C]\n", +"\n", +"// solution\n", +"\n", +"// from steam table, at 4 MN/m^2 and x1=.95\n", +"hf = 1087.4;// [kJ/kg]\n", +"hfg = 1712.9;// [kJ/kg]\n", +"// hence\n", +"h1 = hf+x1*hfg;// [kJ/kg]\n", +"\n", +"// since pressure is kept constant ant temperature is raised so at this condition\n", +"h2 = 3095;// [kJ/kg]\n", +"\n", +"// so by energy balance\n", +"Q = h2-h1;// Heat received,[kJ/kg]\n", +"mprintf('\n The heat received by the steam is = %f kJ/kg \n',Q);\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.19: condition_of_steam.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 4.19');\n", +"\n", +"// aim : To determine the condition of the steam after \n", +"// (a) isothermal compression to half its initial volume,heat rejected\n", +"// (b) hyperbolic compression to half its initial volume\n", +"\n", +"// Given values\n", +"V1 = .3951;// initial volume,[m^3]\n", +"P1 = 1.5;// initial pressure,[MN/m^2]\n", +"\n", +"// solution\n", +"\n", +"// (a)\n", +"// from steam table, at 1.5 MN/m^2 \n", +"hf1 = 844.7;// [kJ/kg]\n", +"hfg1 = 1945.2;// [kJ/kg]\n", +"hg1 = 2789.9;// [kJ/kg]\n", +"vg1 = .1317;// [m^3/kg]\n", +"\n", +"// calculation\n", +"m = V1/vg1;// mass of steam,[kg]\n", +"vg2b = vg1/2;// given,[m^3/kg](vg2b is actual specific volume before compression)\n", +"x1 = vg2b/vg1;// dryness fraction\n", +"h1 = m*(hf1+x1*hfg1);// [kJ]\n", +"Q = m*x1*hfg1;// heat loss,[kJ]\n", +"mprintf('\n (a) The Quantity of steam present is = %f kg \n',m);\n", +"mprintf('\n Dryness fraction is = %f \n',x1);\n", +"mprintf('\n The enthalpy is = %f kJ \n',h1);\n", +"mprintf('\n The heat loss is = %f kJ \n',Q);\n", +"\n", +"// (b)\n", +"V2 = V1/2;\n", +"// Given compression is according to the law PV=Constant,so\n", +"P2 = P1*V1/V2;// [MN/m^2]\n", +"// from steam table at P2\n", +"hf2 = 1008.4;// [kJ/kg]\n", +"hfg2 = 1793.9;// [kJ/kg]\n", +"hg2 = 2802.3;// [kJ/kg]\n", +"vg2 = .0666;// [m^3/kg]\n", +"\n", +"// calculation\n", +"x2 = vg2b/vg2;// dryness fraction\n", +"h2 = m*(hf2+x2*hfg2);// [kJ]\n", +"\n", +"mprintf('\n (b) The dryness fraction is = %f \n',x2);\n", +"mprintf('\n The enthalpy is = %f kJ\n',h2);\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.1: specific_enthalpies.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 4.1');\n", +"\n", +"// aim : To determine\n", +"// the enthalpy\n", +"\n", +"// Given values\n", +"P = .50;// Pressure, [MN/m^2]\n", +"\n", +"// solution\n", +"\n", +"// From steam tables, at given pressure\n", +"hf = 640.1;// specific liquid enthalpy ,[kJ/kg]\n", +"hfg = 2107.4;// specific enthalpy of evaporation ,[kJ/kg]\n", +"hg = 2747.5; // specific enthalpy of dry saturated steam ,[kJ/kg]\n", +"tf = 151.8; // saturation temperature,[C]\n", +"\n", +"mprintf('\n The specific liquid enthalpy is = %f kJ/kg \n',hf);\n", +"mprintf('\n The specific enthalpy of evaporation is = %f kJ/kg \n',hfg);\n", +"mprintf('\n The specific enthalpy of dry saturated steam is = %f kJ/kg \n',hg);\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.20: mass_work_change_in_internal_energy_and_heat_transfer.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 4.20');\n", +"\n", +"// aim : To determine the\n", +"// (a) mass of steam \n", +"// (b) work transfer\n", +"// (c) change of internal energy\n", +"// (d) heat exchange b/w the steam and surroundings\n", +"\n", +"// Given values\n", +"P1 = 2.1;// initial pressure,[MN/m^2]\n", +"x1 = .9;// dryness fraction\n", +"V1 = .427;// initial volume,[m^3]\n", +"P2 = .7;// final pressure,[MN/m^2]\n", +"// Given process is polytropic with\n", +"n = 1.25; // polytropic index\n", +"\n", +"// solution\n", +"// from steam table\n", +"\n", +"// at 2.1 MN/m^2\n", +"hf1 = 920.0;// [kJ/kg]\n", +"hfg1=1878.2;// [kJ/kg]\n", +"hg1=2798.2;// [kJ/kg]\n", +"vg1 = .0949;// [m^3/kg]\n", +"\n", +"// and at .7 MN/m^2\n", +"hf2 = 697.1;// [kJ/kg]\n", +"hfg2 = 2064.9;// [kJ/kg]\n", +"hg2 = 2762.0;// [kJ/kg]\n", +"vg2 = .273;// [m^3/kg]\n", +"\n", +"// (a)\n", +"v1 = x1*vg1;// [m^3/kg]\n", +"m = V1/v1;// [kg]\n", +"mprintf('\n (a) The mass of steam present is = %f kg\n',m);\n", +"\n", +"// (b)\n", +"// for polytropic process\n", +"v2 = v1*(P1/P2)^(1/n);// [m^3/kg]\n", +"\n", +"x2 = v2/vg2;// final dryness fraction\n", +"// work transfer\n", +"W = m*(P1*v1-P2*v2)*10^3/(n-1);// [kJ]\n", +"mprintf('\n (b) The work transfer is = %f kJ\n',W);\n", +"\n", +"// (c)\n", +"// initial\n", +"h1 = hf1+x1*hfg1;// [kJ/kg]\n", +"u1 = h1-P1*v1*10^3;// [kJ/kg]\n", +"\n", +"// final\n", +"h2 = hf2+x2*hfg2;// [kJ/kg]\n", +"u2 = h2-P2*v2*10^3;// [kJ/kg]\n", +"\n", +"del_U = m*(u2-u1);// [kJ]\n", +"mprintf('\n (c) The change in internal energy is = %f kJ',del_U);\n", +"if(del_U<0)\n", +" disp('since del_U<0,so this is loss of internal energy')\n", +"else\n", +" disp('since del_U>0,so this is gain in internal energy')\n", +"end\n", +"\n", +"// (d)\n", +"Q = del_U+W;// [kJ]\n", +"mprintf('\n (d) The heat exchange between the steam and surrounding is = %f kJ',Q);\n", +"if(Q<0)\n", +" disp('since Q<0,so this is loss of heat energy to surrounding')\n", +"else\n", +" disp('since Q>0,so this is gain in heat energy to the steam')\n", +"end\n", +"\n", +"// there are minor vairations in the values reported in the book\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.21: volume_dryness_fraction_and_change_of_internal_energy.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 4.21');\n", +"\n", +"// aim : To determine the \n", +"// (a) volume occupied by steam\n", +"// (b)(1) final dryness fraction of steam\n", +"// (2) Change of internal energy during expansion\n", +"\n", +"// (a)\n", +"// Given values\n", +"P1 = .85;// [mN/m^2]\n", +"x1 = .97;\n", +"\n", +"// solution\n", +"// from steam table, at .85 MN/m^2,\n", +"vg1 = .2268;// [m^3/kg]\n", +"// hence\n", +"v1 = x1*vg1;// [m^3/kg]\n", +"mprintf('\n (a) The volume occupied by 1 kg of steam is = %f m^3/kg\n',v1);\n", +"\n", +"// (b)(1)\n", +"P2 = .17;// [MN/m^2]\n", +"// since process is polytropic process with\n", +"n = 1.13; // polytropic index\n", +"// hence\n", +"v2 = v1*(P1/P2)^(1/n);// [m^3/kg]\n", +"\n", +"// from steam table at .17 MN/m^2\n", +"vg2 = 1.031;// [m^3/kg]\n", +"// steam is wet so\n", +"x2 = v2/vg2;// final dryness fraction\n", +"mprintf('\n (b)(1) The final dryness fraction of the steam is = %f \n',x2);\n", +"\n", +"// (2)\n", +"W = (P1*v1-P2*v2)*10^3/(n-1);// [kJ/kg]\n", +"// since process is adiabatic, so\n", +"del_u = -W;// [kJ/kg]\n", +"mprintf('\n (2) The change in internal energy of the steam during expansion is = %f kJ/kg (This is a loss of internal energy)\n',del_u);\n", +"// There are minor variation in the answer\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.2: Saturation_temperature_and_specific_enthalpies.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 4.2');\n", +"\n", +"// aim : To determine \n", +"// saturation temperature and enthalpy\n", +"\n", +"// Given values\n", +"P = 2.04;// pressure, [MN/m^2]\n", +"\n", +"// solution\n", +"// since in the steam table values of enthalpy and saturation temperature at 2 and 2.1 MN?m^2 are given, so for knowing required values at given pressure,there is need to do interpolation\n", +"\n", +"// calculation of saturation temperature\n", +"// from steam table\n", +"Table_P_tf = [[2.1,2.0];[214.9,212.4]]; // P in [MN/m^2] and tf in [C]\n", +"// using interpolation\n", +"tf = interpln(Table_P_tf,2.04);// saturation temperature at given condition\n", +"mprintf('\n The Saturation temperature is = %f C \n',tf);\n", +"\n", +"// calculation of specific liquid enthalpy\n", +"// from steam table\n", +"Table_P_hf = [[2.1,2.0];[920.0,908.6]];// P in [MN/m^2] and hf in [kJ/kg]\n", +"// using interpolation\n", +"hf = interpln(Table_P_hf,2.04); // enthalpy at given condition, [kJ/kg]\n", +"mprintf('\n The Specific liquid enthalpy is = %f kJ/kg \n',hf);\n", +"\n", +"// calculation of specific enthalpy of evaporation\n", +"// from steam table\n", +"Table_P_hfg = [[2.1,2.0];[1878.2,1888.6]];// P in [MN/m^2] and hfg in [kJ/kg]\n", +"// using interpolation\n", +"hfg = interpln(Table_P_hfg,2.04); // enthalpy at given condition, [kJ/kg]\n", +"mprintf('\n The Specific enthalpy of evaporation is = %f kJ/kg \n',hfg);\n", +"\n", +"// calculation of specific enthalpy of dry saturated steam\n", +"// from steam table\n", +"Table_P_hg = [[2.1,2.0];[2798.2,2797.2]];//P in [MN/m^2] and hg in [kJ/kg]\n", +"// using interpolation\n", +"hg = interpln(Table_P_hg,2.04); // enthalpy at given condition, [kJ/kg]\n", +"mprintf('\n The Specific enthalpy of dry saturated steam is = %f kJ/kg \n',hg);\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.3: specific_enthalpy.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 4.3');\n", +"\n", +"// aim : To determine\n", +"// the specific enthalpy\n", +"\n", +"// given values\n", +"P = 2; // pressure ,[MN/m^2]\n", +"t = 250; // Temperature, [C]\n", +"cp = 2.0934; // average value of specific heat capacity, [kJ/kg K]\n", +"\n", +"// solution\n", +"\n", +"// looking up steam table it shows that at given pressure saturation temperature is 212.4 C,so\n", +"tf = 212.4; // [C]\n", +"// hence,\n", +"Degree_of_superheat = t-tf;// [C]\n", +"// from table at given temperature 250 C\n", +"h = 2902; // specific enthalpy of steam at 250 C ,[kJ/kg]\n", +"mprintf('\nThe specific enthalpy of steam at 2 MN/m^2 with temperature 250 C is = %f kJ/kg \n',h);\n", +"\n", +"// Also from steam table enthalpy at saturation temperature is\n", +"hf = 2797.2 ;// [kJ/kg]\n", +"// so enthalpy at given temperature is\n", +"h = hf+cp*(t-tf);// [kJ/kg]\n", +"\n", +"mprintf('\n The specific enthalpy at given T and P by alternative path is = %f kJ/kg \n',h);\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.4: specific_enthalpy.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 4.4');\n", +"\n", +"// aim : To determine\n", +"// the specific enthalpy of steam\n", +"\n", +"// Given values\n", +"P = 2.5;// pressure, [MN/m^2]\n", +"t = 320; // temperature, [C]\n", +"\n", +"// solution\n", +"// from steam table at given condition the saturation temperature of steam is 223.9 C, therefore steam is superheated\n", +"tf = 223.9;// [C]\n", +"\n", +"// first let's calculate estimated enthalpy\n", +"// again from steam table \n", +"\n", +"hg = 2800.9;// enthalpy at saturation temp, [kJ/kg]\n", +"cp =2.0934;// specific heat capacity of steam,[kJ/kg K]\n", +"\n", +"// so enthalpy at given condition is\n", +"h = hg+cp*(t-tf);// [kJ/kg]\n", +"mprintf('\n The estimated specific enthalpy is = %f kJ/kg \n',h);\n", +"\n", +"// calculation of accurate specific enthalpy\n", +"// we need double interpolation for this\n", +"\n", +"// first interpolation w.r.t. to temperature\n", +"// At 2 MN/m^2\n", +"Table_t_h = [[325,300];[3083,3025]];// where, t in [C] and h in [kJ/kg]\n", +"h1 = interpln(Table_t_h,320); // [kJ/kg]\n", +"\n", +"// at 4 MN/m^2\n", +"Table_t_h = [[325,300];[3031,2962]]; // t in [C] and h in [kJ/kg]\n", +"h2 = interpln(Table_t_h,320); // [kJ/kg]\n", +"\n", +"// now interpolation w.r.t. pressure\n", +"Table_P_h = [[4,2];[h2,h1]]; // where P in NM/m^2 and h1,h2 in kJ/kg\n", +"h = interpln(Table_P_h,2.5);// [kJ/kg]\n", +"mprintf('\n The accurate specific enthalpy of steam at pressure of 2.5 MN/m^2 and with a temperature 320 C is = %f kJ/kg \n',h);\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.5: specific_enthalpy.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 4.5');\n", +"\n", +"// aim : To determine \n", +"// the specific enthalpy \n", +"\n", +"// Given values\n", +"P = 70; // pressure, [kn/m^2]\n", +"x = .85; // Dryness fraction\n", +"\n", +"// solution\n", +"\n", +"// from steam table, at given pressure \n", +"hf = 376.8;// [kJ/kg]\n", +"hfg = 2283.3;// [kJ/kg]\n", +"\n", +"// now using equation [2]\n", +"h = hf+x*hfg;// specific enthalpy of wet steam,[kJ/kg]\n", +"\n", +"mprintf('\n The specific enthalpy of wet steam is = %f kJ/kg \n',h);\n", +"\n", +"// There is minor variation in the book's answer\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.8: specific_volume.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 4.8');\n", +"\n", +"// aim : To determine \n", +"// the specific volume of wet steam\n", +"\n", +"// Given values\n", +"P = 1.25; // pressure, [MN/m^2]\n", +"x = .9; // dry fraction\n", +"\n", +"// solution\n", +"// from steam table at given pressure\n", +"vg = .1569;// [m^3/kg]\n", +"// hence\n", +"v = x*vg; // [m^3/kg]\n", +"\n", +"mprintf('\nThe specific volume of wet steam is = %f m^3/kg \n',v);\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 4.9: specific_volume.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 4.9');\n", +"\n", +"// aim : To determine\n", +"// the specific volume \n", +"\n", +"// Given values\n", +"t = 325; // temperature, [C]\n", +"P = 2; // pressure, [MN/m^2]\n", +"\n", +"// solution\n", +"// from steam table at given t and P\n", +"vf = .1321; // [m^3/kg]\n", +"tf = 212.4; // saturation temperature, [C]\n", +"\n", +"mprintf('\n The specific volume of steam at pressure of 2 MN/m^2 and with temperature 325 C is = %f m^3/kg \n',vf);\n", +"doh= t-tf; // degree of superheat, [C]\n", +"mprintf('\n The degree of superheat is = %f C\n',doh);\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 +} |