{ "metadata": { "name": "", "signature": "sha256:718f559da4ae2a13e9c934b6162f71a824de61441f47a14a1f58cca792ea40ff" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 7 :\n", "equations of state and general\n", "thermodynamic relations" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 7.1 pg : 158" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\t\t\t\n", "# Variables\n", "T1 = 1160. \t\t\t#R\n", "h1 = 281.14 \t\t\t#B/lbm\n", "Pr1 = 21.18 \n", "P2 = 30. \t\t\t#psia\n", "P1 = 100. \t\t\t#psia\n", "\t\t\t\n", "# Calculations\n", "Pr2 = Pr1*P2/P1\n", "T2 = 833. \t\t\t#R\n", "h2 = 199.45 \t\t\t#B/lbm\n", "dh = h2-h1\n", "\t\t\t\n", "# Results\n", "print \"Change in enthalpy = %.2f B/lbm\"%(dh)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Change in enthalpy = -81.69 B/lbm\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 7.2 pg : 159" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "# Variables\n", "T2 = 860. \t\t\t#R\n", "phi1 = 0.78767\n", "phi2 = 0.71323\n", "P2 = 30. \t\t\t#psia\n", "P1 = 100. \t\t\t#psia\n", "\t\t\t\n", "# Calculations\n", "dS = phi2-phi1- 53.35/778 *math.log(P2/P1)\n", "\t\t\t\n", "# Results\n", "print \"Net change of entropy = %.5f B/lbm R\"%(dS)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Net change of entropy = 0.00812 B/lbm R\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 7.3 pg : 159" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\t\t\t\n", "# Variables\n", "T1 = 540. \t\t\t#R\n", "T2 = 960. \t\t\t#R\n", "h2 = 231.06 \t\t\t#B/lbm\n", "h1 = 129.06 \t\t\t#B/lbm\n", "cp = 0.24\n", "\t\t\t\n", "# Calculations\n", "W = h2-h1\n", "dh = cp*(T2-T1)\n", "\t\t\t\n", "# Results\n", "print \"Change in enthalpy = %.1f B/lbm\"%(dh)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Change in enthalpy = 100.8 B/lbm\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 7.4 pg : 161" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\t\t\t\n", "# Variables\n", "T1 = 420. \t\t\t#R\n", "T2 = 380. \t\t\t#R\n", "hig = 1221.2\n", "P1 = 0.0019\n", "\t\t\t\n", "# Calculations\n", "lnp = hig*778*(1/T1 - 1/T2)/85.6\n", "pra = math.exp(lnp)\n", "P2 = pra*P1\n", "\t\t\t\n", "# Results\n", "print \"Final pressure = %.3e psia\"%(P2)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Final pressure = 1.177e-04 psia\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 7.5 pg : 170" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\t\t\t\n", "# Variables\n", "pc = 482.\t\t\t#psia\n", "Tc = 227. \t\t\t#R\n", "vc = 1.44 \t\t\t#ft**3/lbm mol\n", "P = 600. \t\t\t#psia\n", "T = 310. \t\t\t#R\n", "\t\t\t\n", "# Calculations\n", "Pr = P/pc\n", "Tr = T/Tc\n", "Z = 0.83\n", "v = Z*55.12*T/(P*144)\n", "rho = 1/v\n", "\t\t\t\n", "# Results\n", "print \"Density = %.1f lbm/ft**3\"%(rho)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Density = 6.1 lbm/ft**3\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 7.6 pg : 174" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\t\t\t\n", "# Variables\n", "T = -150.+460 \t\t\t#R\n", "v = 0.6 \t\t \t#ft**3/lbm\n", "vc = 1.44\n", "Tc = 227. \t \t\t#R\n", "Pc = 482. \t\t\t#psia\n", "\t\t\t\n", "# Calculations\n", "vr = v/vc\n", "Tr = T/Tc\n", "Pr = 1.75\n", "P = Pr*Pc\n", "\t\t\t\n", "# Results\n", "print \"Final pressure = %d psia\"%(P)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Final pressure = 843 psia\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 7.7 pg : 177" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\t\t\t\n", "# Variables\n", "Tc = 344. \t\t\t#R\n", "Pc = 673. \t\t\t#psia\n", "P1 = 20. \t\t\t#psia\n", "P2 = 500. \t\t\t#psia\n", "M = 16.\n", "T = 560. \t\t\t#R\n", "\t\t\t\n", "# Calculations\n", "pr1 = P1/Pc\n", "pr2 = P2/Pc\n", "Tr = T/Tc\n", "dh2 = 0.65*Tc\n", "dsp = 0.35 \t\t\t#B/lbm mol R\n", "dsp2 = 0.018-dsp- 1545/778 *math.log(P2/P1)\n", "W = dh2-dsp2*T\n", "W2 = W/M\n", "\t\t\t\n", "# Results\n", "print \"Work per pound mass = %d B/lbm\"%(W2)\n", "\n", "#The answer is a bit different due to rounding off error. check using calculator.\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Work per pound mass = 138 B/lbm\n" ] } ], "prompt_number": 8 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 7.8 pg : 179" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\t\t\t\n", "# Variables\n", "P = 1000. \t \t\t#psia\n", "T1 = 100. + 460 \t\t\t#R\n", "T2 = 800. + 460 \t\t\t#R\n", "\t\t\t\n", "# Calculations\n", "pc = 1070. \t\t\t#psia\n", "Tc = 548. \t\t\t#R\n", "pr1 = P/pc\n", "Tr1 = T1/Tc\n", "Tr2 = T2/Tc\n", "M = 44.\n", "h1 = 4235.8 \t\t\t#B/lbm mol\n", "h2 = 11661 \t\t\t#B/lbm mol\n", "h2bar = 3.5 \t\t\t#B/lbm mol\n", "h1bar = 0.48 \t\t\t#B/lbm mol\n", "dhbar = Tc*(h2bar-h1bar) + h2-h1\n", "Q = dhbar/M\n", "cp = 0.202 \t\t\t#B/lbm F\n", "Q2 = cp*(T2-T1)\n", "Error = (Q-Q2)/Q\n", "\t\t\t\n", "# Results\n", "print \"Error in calculation = %d percent\"%(Error*100)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Error in calculation = 31 percent\n" ] } ], "prompt_number": 9 } ], "metadata": {} } ] }