{ "metadata": { "name": "", "signature": "sha256:694b356fc4f85fd8aa841dd0d02eae327738df2eb161cb913631664ccceb9a07" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 4 : principles of energy analysis" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 4.1 pg : 79" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\t\t\t\n", "# Variables\n", "m = 1.\n", "he = 1148.8 \t\t\t#B/lbm\n", "hi = 1357. \t\t\t#B/lbm\n", "Ve = 100. \t\t\t#ft/sec\n", "Vi = 800. \t\t\t#ft/sec\n", "\t\t\t\n", "# Calculations\n", "dW = m*(he-hi) + m*(Ve**2 - Vi**2)/(2*32.2*778)\n", "dWhr = dW*3600\n", "hp = -dWhr/2545.\n", "\t\t\t\n", "# Results\n", "print \"Horsepower output = %d hp\"%(hp+1)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Horsepower output = 313 hp\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 4.2 pg:79" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\t\t\t\n", "# Variables\n", "rate = 80. \t\t\t#lbm/min\n", "T1 = 100. \t\t\t#F\n", "P1 = 100. \t\t\t#psia\n", "P2 = 1000. \t\t\t#psia\n", "\t\t\t\n", "# Calculations\n", "v = 0.01613 \t\t\t#ft**3/lbm\n", "W = rate*(P2-P1)*144*v\n", "\t\t\t\n", "# Results\n", "print \"Work done = %.2f ft-lbf/min\"%(round(W,-3))\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Work done = 167000.00 ft-lbf/min\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 4.3 pg : 81" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\t\t\t\n", "# Variables\n", "hi = 1279.1 \t\t\t#B/lbm\n", "\t\t\t\n", "# Calculations\n", "u2 = hi\n", "T2 = 564. \t\t\t#F\n", "\t\t\t\n", "# Results\n", "print \"Temperature of steam = %d F\"%(T2)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Temperature of steam = 564 F\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 4.4 pg : 82" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\t\t\t\n", "# Variables\n", "import math \n", "P1 = 20. \t\t\t#psia\n", "P2 = 100. \t\t\t#psia\n", "V = 3. \t \t\t#ft**3\n", "T = 560. \t\t\t#R\n", "ma = 0.289\n", "\t\t\t\n", "# Calculations\n", "ma = P1*V/(53.35*T)\n", "Wa = -ma*53.35*T*math.log(P1/P2)\n", "Qa = -Wa\n", "Va2 = 3/5.\n", "V2s = V-Va2\n", "hi = 1279.1 \t\t\t#B/lbm\n", "T2s = 536. \t\t\t#F\n", "\t\t\t\n", "# Results\n", "print \"Final temperature = %d F\"%(T2s)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Final temperature = 536 F\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 4.5 pg : 87" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "# Variables\n", "P1 = 200. \t\t\t#psia\n", "P2 = 100. \t\t\t#psia\n", "T1 = 300.+460 \t\t\t#R\n", "g = 1.4\n", "cp = 0.24\n", "\t\t\t\n", "# Calculations\n", "T2 = (T1)*(P2/P1)**((g-1)/g)\n", "V2 = math.sqrt(2*32.2*778*cp*(T1-T2))\n", "\t\t\t\n", "# Results\n", "print \"Final velocity = %d ft/sec\"%(V2)\n", "\n", "# check answer using calculator" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Final velocity = 1281 ft/sec\n" ] } ], "prompt_number": 7 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 4.6 pg : 88" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\t\t\t\n", "# Variables\n", "T1 = 500.+460 \t\t\t#R\n", "P1 = 50. \t\t\t#psia\n", "P2 = 15. \t\t\t#psia\n", "g = 1.4\n", "cp = 0.24\n", "\t\t\t\n", "# Calculations\n", "T2 = T1*(P2/P1)**((g-1)/g)\n", "W = cp*(T2-T1) + (T1-460)**2 /(2*32.2*778)\n", "\t\t\t\n", "# Results\n", "print \"Net work output from turbine = %.1f B/lbm\"%(W)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Net work output from turbine = -62.1 B/lbm\n" ] } ], "prompt_number": 8 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 4.7 pg : 91" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\t\t\t\n", "# Variables\n", "T1 = 150.+460 \t\t\t#R\n", "T1 = 40.+460 \t\t\t#R\n", "\t\t\t\n", "# Calculations\n", "h2 = 43.850 \t\t\t#B/lbm\n", "hf2 = 17.273\n", "hfg2 = 64.163\n", "x2 = (h2-hf2)/hfg2\n", "\t\t\t\n", "# Results\n", "print \"Quality of freon vapor = %.3f\"%(x2)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Quality of freon vapor = 0.414\n" ] } ], "prompt_number": 9 } ], "metadata": {} } ] }