diff options
Diffstat (limited to 'Basic_Engineering_Thermodynamics_by_Rayner_Joel/Chapter18.ipynb')
| -rw-r--r-- | Basic_Engineering_Thermodynamics_by_Rayner_Joel/Chapter18.ipynb | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/Basic_Engineering_Thermodynamics_by_Rayner_Joel/Chapter18.ipynb b/Basic_Engineering_Thermodynamics_by_Rayner_Joel/Chapter18.ipynb new file mode 100644 index 00000000..696c7fa6 --- /dev/null +++ b/Basic_Engineering_Thermodynamics_by_Rayner_Joel/Chapter18.ipynb @@ -0,0 +1,205 @@ +{ + "cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Chapter 18 - Refrigeration" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 1: pg 612" + ] + }, + { + "cell_type": "code", + "execution_count": 1, + "metadata": { + "collapsed": false + }, + "outputs": [ + { + "name": "stdout", + "output_type": "stream", + "text": [ + "Example 18.1\n", + " (a) The coefficient of performance of the refrigerator is = 4.49\n", + " (b) The mass flow of refrigerant/h is (kg) = 166.94\n", + " (c) The mass flow of water required is (kg/h) = 579.74\n", + "The answer is a bit different due to rounding off error in textbook\n" + ] + } + ], + "source": [ + "#pg 612\n", + "print('Example 18.1');\n", + "\n", + "# aim : To determine\n", + "# (a) the coefficient of performance\n", + "# (b) the mass flow of the refrigerant\n", + "# (c) the cooling water required by the condenser\n", + "import math\n", + "from math import log\n", + "# given values\n", + "P1 = 462.47;# pressure limit, [kN/m**2]\n", + "P3 = 1785.90;# pressure limit, [kN/m**2]\n", + "T2 = 273.+59;# entering saturation temperature, [K]\n", + "T5 = 273.+32;# exit temperature of condenser, [K]\n", + "d = 75*10**-3;# bore, [m]\n", + "L = d;# stroke, [m]\n", + "N = 8;# engine speed, [rev/s]\n", + "VE = .8;# olumetric efficiency\n", + "cpL = 1.32;# heat capacity of liquid, [kJ/kg K]\n", + "c = 4.187;# heat capacity of water, [kj/kg K]\n", + "\n", + "# solution\n", + "# from given table\n", + "# at P1\n", + "h1 = 231.4;# specific enthalpy, [kJ/kg]\n", + "s1 = .8614;# specific entropy,[ kJ/kg K\n", + "v1 = .04573;# specific volume, [m**3/kg]\n", + "\n", + "# at P3\n", + "h3 = 246.4;# specific enthalpy, [kJ/kg]\n", + "s3 = .8093;# specific entropy,[ kJ/kg K\n", + "v3 = .04573;# specific volume, [m**3/kg]\n", + "T3= 273+40;# saturation temperature, [K]\n", + "h4 = 99.27;# specific enthalpy, [kJ/kg]\n", + "# (a)\n", + "s2 = s1;# specific entropy, [kJ/kg k]\n", + "# using s2=s3+cpv*log(T2/T3)\n", + "cpv = (s2-s3)/log(T2/T3);# heat capacity, [kj/kg k]\n", + "\n", + "# from Fig.18.8\n", + "T4 = T3;\n", + "h2 = h3+cpv*(T2-T3);# specific enthalpy, [kJ/kg]\n", + "h5 = h4-cpL*(T4-T5);# specific enthalpy, [kJ/kg]\n", + "h6 = h5;\n", + "COP = (h1-h6)/(h2-h1);# coefficient of performance\n", + "print ' (a) The coefficient of performance of the refrigerator is = ',round(COP,2)\n", + "\n", + "# (b)\n", + "SV = math.pi/4*d**2*L;# swept volume of compressor/rev, [m**3]\n", + "ESV = SV*VE*N*3600;# effective swept volume/h, [m**3]\n", + "m = ESV/v1;# mass flow of refrigerant/h,[kg]\n", + "print ' (b) The mass flow of refrigerant/h is (kg) = ',round(m,2)\n", + "\n", + "# (c)\n", + "dT = 12;# temperature limit, [C]\n", + "Q = m*(h2-h5);# heat transfer in condenser/h, [kJ]\n", + "# using Q=m_dot*c*dT, so\n", + "m_dot = Q/(c*dT);# mass flow of water required, [kg/h]\n", + "print ' (c) The mass flow of water required is (kg/h) = ',round(m_dot,2)\n", + "\n", + "print 'The answer is a bit different due to rounding off error in textbook'\n", + "# End\n" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Example 2: pg 614" + ] + }, + { + "cell_type": "code", + "execution_count": 2, + "metadata": { + "collapsed": false + }, + "outputs": [ + { + "name": "stdout", + "output_type": "stream", + "text": [ + "Example 18.2\n", + " (a) The mass flow of R401 is (kg/h) = 592.6\n", + " (b) The dryness fraction of R401 at the entry to the evaporator is = 0.244\n", + " (c) The power to driving motor is (kW) = 5.86\n", + " (d) The ratio of heat transferred from condenser to the power required to the motor is = 4.74 :1\n" + ] + } + ], + "source": [ + "#pg 614\n", + "print('Example 18.2');\n", + "\n", + "# aim : To determine\n", + "# (a) the mass flow of R401\n", + "# (b) the dryness fraction of R401 at the entry to the evaporator\n", + "# (c) the power of driving motor\n", + "# (d) the ratio of heat transferred from condenser to the power required to the motor\n", + "from math import log\n", + "# given values\n", + "P1 = 411.2;# pressure limit, [kN/m^2]\n", + "P3 = 1118.9;# pressure limit, [kN/m^2]\n", + "Q = 100*10**3;# heat transfer from the condenser,[kJ/h]\n", + "T2 = 273+60;# entering saturation temperature, [K]\n", + "\n", + "# given\n", + "# from given table\n", + "# at P1\n", + "h1 = 409.3;# specific enthalpy, [kJ/kg]\n", + "s1 = 1.7431;# specific entropy,[ kJ/kg K\n", + "\n", + "# at P3\n", + "h3 = 426.4;# specific enthalpy, [kJ/kg]\n", + "s3 = 1.7192;# specific entropy,[ kJ/kg K\n", + "T3 = 273.+50;# saturation temperature, [K]\n", + "h4 = 265.5;# specific enthalpy, [kJ/kg]\n", + "# (a)\n", + "s2 = s1;# specific entropy, [kJ/kg k]\n", + "# using s2=s3+cpv*log(T2/T3)\n", + "cpv = (s2-s3)/log(T2/T3);# heat capacity, [kj/kg k]\n", + "\n", + "# from Fig.18.8\n", + "h2 = h3+cpv*(T2-T3);# specific enthalpy, [kJ/kg]\n", + "Qc = h2-h4;# heat transfer from condenser, [kJ/kg]\n", + "mR401 = Q/Qc;# mass flow of R401, [kg]\n", + "print ' (a) The mass flow of R401 is (kg/h) = ',round(mR401,1)\n", + "\n", + "# (b)\n", + "hf1 = 219;# specific enthalpy, [kJ/kg]\n", + "h5 = h4;\n", + "# using h5=hf1+s5*(h1-hf1),so\n", + "x5 = (h5-hf1)/(h1-hf1);# dryness fraction\n", + "print ' (b) The dryness fraction of R401 at the entry to the evaporator is = ',round(x5,3)\n", + "\n", + "# (c)\n", + "P = mR401*(h2-h1)/3600/.7;# power to driving motor, [kW]\n", + "print ' (c) The power to driving motor is (kW) = ',round(P,2)\n", + "\n", + "# (d)\n", + "r = Q/3600./P;# ratio\n", + "print ' (d) The ratio of heat transferred from condenser to the power required to the motor is = ',round(r,2),\":1\"\n", + "\n", + "# End\n" + ] + } + ], + "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 +} |