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diff --git a/Basic_Engineering_Thermodynamics_by_R_Joel/19-Psychrometry.ipynb b/Basic_Engineering_Thermodynamics_by_R_Joel/19-Psychrometry.ipynb new file mode 100644 index 0000000..3e042c9 --- /dev/null +++ b/Basic_Engineering_Thermodynamics_by_R_Joel/19-Psychrometry.ipynb @@ -0,0 +1,308 @@ +{ +"cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Chapter 19: Psychrometry" + ] + }, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 19.1: moisture_content.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 19.1');\n", +"\n", +"// aim : To compare the moisture content and the true specific volumes of atmosphere air \n", +"// (a) temperature is 12 C and the air is saturaded\n", +"// (b) temperature is 31 C and air is .75 saturated\n", +"\n", +"// Given values\n", +"P_atm = 101.4;// atmospheric pressure, [kN/m^2]\n", +"R = .287;// [kJ/kg K]\n", +"\n", +"// solution\n", +"// (a)\n", +"T = 273+12;// air temperature, [K]\n", +"// From steam table at 12 C\n", +"p = 1.4;// [kN/m^2]\n", +"vg = 93.9;// [m^3/kg]\n", +"pa = P_atm-p;// partial pressure of the dry air, [kN/m^2]\n", +"va = R*T/pa;// [m^3/kg]\n", +"\n", +"mw = va/vg;// mass of water vapor in the air,[kg]\n", +"v = va/(1+mw);// specific volume of humid air, [m^3/kg]\n", +"\n", +"mprintf('\n (a) The mass of water vapor in the humid air is = %f kg\n',mw);\n", +"mprintf('\n The specific volume of humid air is = %f m^3/kg\n',v);\n", +"\n", +"// (b)\n", +"x = .75;// dryness fraction\n", +"T = 273+31;// air temperature, [K]\n", +"// From steam table\n", +"p = 4.5;// [kN/m^2]\n", +"vg = 31.1;// [m^3/kg]\n", +"pa = P_atm-p;// [kN/m^2]\n", +"va = R*T/pa;// [m^3/kg]\n", +"mw1= va/vg;// mass of water vapor in the air, [kg]\n", +"mw_actual = mw1*x;// actual mass of vapor, [kg]\n", +"v = va/(1+mw_actual);// true specific volume of humid air,[m^3/kg] \n", +"\n", +"mprintf('\n (b) The mass of water vapor in the humid air is = %f kg\n',mw1);\n", +"mprintf('\n The specific volume of humid air is = %f m^3/kg\n',v);\n", +"\n", +"ewv = mw_actual/mw ;\n", +"mprintf('\n On the warm day the air conteains %f times the mass of water vapor as on the cool day \n',ewv);\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 19.2: partial_pressures_specific_humidity_and_composition.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 19.2');\n", +"\n", +"// aim : To determine\n", +"// (a) the partial pressures of the vapor and the dry air\n", +"// (b) the specific humidity of the mixture\n", +"// (c) the composition of the mixture\n", +"\n", +"// Given values\n", +"phi = .65;// Relative humidity\n", +"T = 2733+20;// temperature, [K]\n", +"p = 100;// barometric pressure, [kN/m^2]\n", +"\n", +"// solution\n", +"// (a)\n", +"// From the steam table at 20 C\n", +"pg = 2.34;// [kN/m^2]\n", +"ps = phi*pg;// partial pressure of vapor, [kN/m^2]\n", +"pa = p-ps;// partial pressure of dry air, [kN/m^2]\n", +"mprintf('\n (a) The partial pressure of vapor is = %f kN/m^2\n',ps);\n", +"mprintf('\n The partial pressure of dry air is = %f kN/m^2\n',pa);\n", +"\n", +"// (b)\n", +"// from equation [15]\n", +"omega = .622*ps/(p-ps);// specific humidity of the mixture\n", +"mprintf('\n (b) The specific humidity of the mixture is = %f kg/kg dry air\n',omega);\n", +"\n", +"// (c)\n", +"// using eqn [1] from section 19.2\n", +"y = 1/(1+omega);// composition of the mixture\n", +"mprintf('\n (c) The composition of the mixture is = %f\n',y);\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 19.3: specific_humidity_dew_point_degree_of_superheat_mass_of_condensate.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp('Example 19.3');\n", +"\n", +"// aim : To determine\n", +"// (a) the specific humidity\n", +"// (b) the dew point\n", +"// (c) the degree of superheat of the superheated vapor\n", +"// (d) the mass of condensate formed per kg of dry air if the moist air is cooled to 12 C\n", +"\n", +"// Given values\n", +"t = 25;// C\n", +"T = 273+25;// moist air temperature, [K]\n", +"phi = .6;// relative humidity\n", +"p = 101.3;// barometric pressure, [kN/m^2]\n", +"R = .287;// [kJ/kg K]\n", +"\n", +"// solution\n", +"// (a)\n", +"// From steam table at 25 C\n", +"pg = 3.17;// [kN/m^2]\n", +"ps = phi*pg;// partial pressure of the vapor, [kN/m^2]\n", +"omega = .622*ps/(p-ps);// the specific humidity of air\n", +"\n", +"mprintf('\n (a) The specific humidity is = %f kg/kg air\n',omega);\n", +"\n", +"// (b)\n", +"// Dew point is saturated temperature at ps is,\n", +"t_dew = 16+2*(1.092-1.817)/(2.062-1.817);// [C]\n", +"mprintf('\n (b) The dew point is = %f C\n',t_dew);\n", +"\n", +"// (c)\n", +"Dos = t-t_dew;// degree of superheat, [C]\n", +"mprintf('\n (c) The degree of superheat is = %f C\n',Dos);\n", +"\n", +"// (d)\n", +"// at 25 C\n", +"pa = p-ps;// [kN/m^2]\n", +"va = R*T/pa;// [m^3/kg]\n", +"// at 16.69 C\n", +"vg = 73.4-(73.4-65.1)*.69/2;// [m^3/kg]\n", +"ms1= va/vg; \n", +"// at 12 C\n", +"vg = 93.8;// [m^3/kg]\n", +"ms2 = va/vg;\n", +"\n", +"m = ms1-ms2;// mas of condensate\n", +"mprintf('\n (d) The mass of condensate is = %f kg/kg dry air\n',m);\n", +"\n", +"// there is calculation mistake in the book so answer is no matching\n", +"\n", +"// End" + ] + } +, +{ + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 19.4: volume_mass_and_heat_transfer.sce" + ] + }, + { +"cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": true + }, + "outputs": [], +"source": [ +"clear;\n", +"clc;\n", +"disp(' Example 19.4');\n", +"\n", +"// aim : To determine\n", +"// (a) the volume of external saturated air\n", +"// (b) the mass of air\n", +"// (c) the heat transfer\n", +"// (d) the heat transfer required by the combind water vapour\n", +"\n", +"// given values\n", +"Vb = 56000;// volume of building, [m^3]\n", +"T2 = 273+20;// temperature of air in thebuilding, [K]\n", +"phi = .6;// relative humidity\n", +"T1 = 8+273;// external air saturated temperature, [K]\n", +"p0 = 101.3;// atmospheric pressure, [kN/m^2]\n", +"cp = 2.093;// heat capacity of saturated steam, [kJ/kg K]\n", +"R = .287;// gas constant, [kJ/kg K]\n", +"\n", +"// solution\n", +"// from steam table at 20 C saturation pressure of steam is,\n", +"pg = 2.34;// [kN/m^2]\n", +"\n", +"// (a)\n", +"pvap = phi*pg;// partial pressure of vapor, [kN/m^2] \n", +"P = p0-pvap;// partial pressure of air, [kN/m^2]\n", +"V = 2*Vb;// air required, [m^3]\n", +"// at 8 C saturation pressure ia\n", +"pvap = 1.072;// [kN/m^2]\n", +"P2 = p0-pvap;// partial pressure of entry at 8 C, [kN/m^2]\n", +"\n", +"// using P1*V1/T1=P2*V2/T2;\n", +"V2 = P*V*T1/(T2*P2);// air required at 8 C, [m^3/h]\n", +"mprintf('\n (a) The volume of air required is = %f m^3/h\n',V2);\n", +"\n", +"// (b)\n", +"// assuming\n", +"pg = 1.401;// pressure, [kN/m^2]\n", +"Tg = 273+12;// [K]\n", +"vg = 93.8;// [m^3/kg]\n", +"// at constant pressure\n", +"v = vg*T2/Tg;// volume[m^3/kg]\n", +"mv = V/v;// mass of vapor in building at 20 C, [kg/h]\n", +"// from steam table at 8 C\n", +"vg2 = 121;// [m^3/kg]\n", +"mve = V2/vg2;// mass of vapor supplied with saturated entry air, [kg/h]\n", +"mw = mv-mve;// mass of water added, [kg/h]\n", +"mprintf('\n (b) The mass of water added is = %f kg/h\n ',mw);\n", +"\n", +"// (c)\n", +"// for perfect gas\n", +"m = P2*V2/(R*T1);// [kg/h]\n", +"Cp = .287;// heat capacity, [kJ/kg K]\n", +"Q = m*Cp*(T2-T1);// heat transfer by dry air,[kJ/h]\n", +"mprintf('\n (c) The heat transfer required by dry air is = %f MJ/h\n',Q*10^-3);\n", +"\n", +"// (d)\n", +"// from steam table\n", +"h1 = 2516.2;// specific enthalpy of saturated vapor at 8 C,[kJ/kg]\n", +"hs = 2523.6;// specific enthalpy of saturated vapor at 20 C, [kJ/kg]\n", +"h2 = hs+cp*(T2-T1);// specific enthalpy of vapor at 20 c, [kJ/kg]\n", +"Q1 = mve*(h2-h1);// heat transfer required for vapor, [kJ]\n", +"\n", +"// again from steam table\n", +"hf1 = 33.6;// [kJ/kg]\n", +"hg3 = 2538.2;// [kJ/kg]\n", +"Q2 = mw*(hg3-hf1);// heat transfer required for water, [kJ/h]\n", +"Qt = Q1+Q2;// total heat transfer, [kJ/h]\n", +"mprintf('\n (d) The heat transferred required for vapor+supply water is = %f MJ/h\n',Qt*10^-3);\n", +"\n", +"// there is minor variation in the answer reported in the book\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 +} |