{ "metadata": { "name": "", "signature": "sha256:369d727c64e74475d8c5bb63540cbc246cbdecc5bfe067dfd2c4f31c8ec059a2" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 12: Mixtures" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 12.1, page no 235" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "#initialization\n", "w1 = 2 #lbm\n", "w2 = 1 #lbm\n", "P = 30 #lbm/in^2\n", "T = 60+460 #R\n", "\n", "#calculation\n", "R1 = 35.1\n", "R2 = 55.1\n", "Rm = (w1*R1+w2*R2)/(w1+w2)\n", "vm = (w1+w2)*Rm*T/(144*P)\n", "p1 = w1*R1*T/(144*vm)\n", "p2 = w2*R2*T/(144*vm)\n", "\n", "#result\n", "print \"Gas constant of the mixture = \", round(Rm, 1), \"lb/in^2\"\n", "print \"Volume of the mixture = \", round(vm, 1), \"ft^3\"\n", "print \"Partial pressure of CO2 = \", round(p1, 1), \"lb/in^2\"\n", "print \"Partial pressure of N2 = \", round(p2, 1), \"lb/in^2\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Gas constant of the mixture = 41.8 lb/in^2\n", "Volume of the mixture = 15.1 ft^3\n", "Partial pressure of CO2 = 16.8 lb/in^2\n", "Partial pressure of N2 = 13.2 lb/in^2\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 12.3, page no. 238" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "import scipy.integrate\n", "\n", "#initialization\n", "cpm = 0.2523\n", "Rm = 54.7\n", "T1 = 60+460.0 #R\n", "T2 = 400+460.0 #R\n", "\n", "#calculation\n", "cvm = cpm-Rm/778.0\n", "Q = cpm*(T2-T1)\n", "W = Rm*(T2-T1)\n", "#Rm is divided and multiplied by 778.!\n", "def s(T):\n", " cp = cpm/T\n", " return cp\n", "ds = scipy.integrate.quadrature(s, T1, T2)[0]\n", "\n", "#result\n", "print \"Entropy change = \", round(ds, 3), \"B/lbm\"\n", "print \"specific work = \", W, \"ft-lb/lbm\"\n", "print \"Heat added per pound of mixture = \", round(Q, 1), \"B/lbm\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Entropy change = 0.127 B/lbm\n", "specific work = 18598.0 ft-lb/lbm\n", "Heat added per pound of mixture = 85.8 B/lbm\n" ] } ], "prompt_number": 10 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 12.4, page no. 239" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "#initialization\n", "P = 14.7 #lb/in^2\n", "T = 80+460.0 #R\n", "\n", "#calculation\n", "#From steam tables\n", "Ps = 0.5069 #lb/in^2\n", "v = 633.1 #ft^3/lbm\n", "Pair = P-Ps\n", "vair = 53.3*T/(144*Pair)\n", "wair = 1/(1+vair/v)\n", "wwater = vair/v/(1+vair/v)\n", "\n", "#result\n", "print \"Partial pressure of air = \", round(Pair, 1), \"ft^3/lbm\"\n", "print \"Partial pressure of water vapor = \", Ps, \"ft^3/lbm\"\n", "print \"Gravimetric analysis of air = \", round(wair, 4)\n", "print \"Gravimetric analysis of water = \", round(wwater, 4)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Partial pressure of air = 14.2 ft^3/lbm\n", "Partial pressure of water vapor = 0.5069 ft^3/lbm\n", "Gravimetric analysis of air = 0.9782\n", "Gravimetric analysis of water = 0.0218\n" ] } ], "prompt_number": 13 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 12.5, page no. 240" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "#initialization\n", "P = 14.7 #lb/in^2\n", "T = 80+460.0 #R\n", "M = 18\n", "Ps = 0.5069 #lb/in^2\n", "\n", "#calculation\n", "Pair = P-Ps\n", "R = 1544/M\n", "v = R*T/(144*Ps)\n", "vair = 53.3*T/(144*Pair)\n", "wair = 1/(1+vair/v)\n", "wwater = vair/v/(1+vair/v)\n", "\n", "#result\n", "print \"Partial pressure of air = \", round(Pair, 2), \"ft^3/lbm\"\n", "print \"Specific volume = \", round(v), \"ft^3/lbm\"\n", "print \"Gravimetric analysis of air = \", round(wair, 4)\n", "print \"Gravimetric analysis of water = \", round(wwater, 4)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Partial pressure of air = 14.19 ft^3/lbm\n", "Specific volume = 629.0 ft^3/lbm\n", "Gravimetric analysis of air = 0.9781\n", "Gravimetric analysis of water = 0.0219\n" ] } ], "prompt_number": 17 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 12.6, page no. 242" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "#initialization\n", "RH = 0.62\n", "T = 80+460.0 #R\n", "\n", "#calculation\n", "#From stram tables\n", "P = RH*0.5069\n", "\n", "#result\n", "print \"Partial pressure of water vapor = \", round(P, 4), \"lb/in^2\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Partial pressure of water vapor = 0.3143 lb/in^2\n" ] } ], "prompt_number": 18 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Exmaple 12.7, page no. 243" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "#initialization\n", "P = 14.5 #lb/in^2\n", "T = 70+460.0 #R\n", "rh = 0.34\n", "\n", "#calculation\n", "#From steam tables\n", "Pg = 0.3631 #lb/in^2\n", "Pair = P-Pg\n", "wratio = rh*0.622*Pg/Pair\n", "\n", "#result\n", "print \"Specific humidity = %.5f lbm/lbm\" %wratio" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Specific humidity = 0.00543 lbm/lbm\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Exmaple 12.8, page no. 244" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "#initialization\n", "T = 100+460.0 #R\n", "rh = 0.6\n", "\n", "#calculation\n", "#From steam tables\n", "Pg = 0.9492 #lb/in^2\n", "Pwv = rh*Pg\n", "T = 83 #F\n", "\n", "#result\n", "print \"Dew point is obtained from saturation pressure table and is equal to %d F\" %T" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Dew point is obtained from saturation pressure table and is equal to 83 F\n" ] } ], "prompt_number": 19 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 12.9, page no. 246" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "#initialization\n", "T1 = 80+460.0 #R\n", "T2 = 90+460.0 #R\n", "P = 14.5 #lb/in^2\n", "cp = 0.24\n", "\n", "#calculation\n", "#From steam tables\n", "hg2 = 1096.6\n", "hf3 = 48.02\n", "Pg2 = 0.5069\n", "hf2 = hf3\n", "Pair = P-Pg2\n", "wg2 = 0.622*Pg2/Pair\n", "hgv1 = 1100.9\n", "wwv1 = (cp*(T1-T2)+wg2*(hg2-hf3))/(hgv1-hf3)\n", "Pg = 0.6982\n", "xi = wwv1*(P-Pg)/(Pg*0.622)\n", "\n", "#result\n", "print \"Specific humidity = \", round(wwv1, 4), \"lbm/lbm\"\n", "print \"relative humidity = \", round(xi, 3)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Specific humidity = 0.0202 lbm/lbm\n", "relative humidity = 0.641\n" ] } ], "prompt_number": 20 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 12.10, page no. 247" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "#initialization\n", "T1 = 69.0 #F\n", "T2 = 84.0 #F\n", "P = 14.7 #lb/in^2\n", "\n", "#calculation\n", "# from wet bulb n dry bulb temperature charts\n", "sh = 82.0/7000.0\n", "rh = 47.0\n", "Pwv = 0.27\n", "T = 62.0 #F\n", "h = 33.3\n", "\n", "#result\n", "print \"Specific humidity = \", round(sh, 4), \"lbm/lbm\"\n", "print \"Relative humidity = \" , rh, \"%\"\n", "print \"Partial pressure = \", round(Pwv, 2), \"lb/in^2\"\n", "print \"Dew point = \", T, \"F\"\n", "print \"Enthalpy per pound of air = \", round(h, 1), \"V/lbm dry air\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Specific humidity = 0.0117 lbm/lbm\n", "Relative humidity = 47.0 %\n", "Partial pressure = 0.27 lb/in^2\n", "Dew point = 62.0 F\n", "Enthalpy per pound of air = 33.3 V/lbm dry air\n" ] } ], "prompt_number": 24 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 12.11, page no. 250" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "import math\n", "\n", "#initialization\n", "g1 = [0.489, 100, 700, 35.1, 0.154]\n", "g2 = [0.483, 15, 600, 55.2, 0.177]\n", "g3 = [0.028, 30, 500, 386, 0.754]\n", "\n", "#calculation\n", "v1 = g1[0] *g1[3] *g1[2] /(144*g1[1])\n", "v2 = g2[0] *g2[3] *g2[2] /(144*g2[1])\n", "v3 = g3[0] *g3[3] *g3[2] /(144*g3[1])\n", "vm = v1+v2+v3\n", "Tm = (g1[0] *g1[4] *g1[2] +g2[0] *g2[4] *g2[2] +g3[0] *g3[4] *g3[2])/(g1[0] *g1[4] +g2[0] *g2[4] +g3[0] *g3[4])\n", "Pm = (g1[0] *g1[3] +g2[0] *g2[3] +g3[0] *g3[3]) *Tm/(vm*144)\n", "ds1 = g1[0] *(g1[4] *math.log(Tm/g1[2]) +g1[3] /778.0 *math.log(vm/v1))\n", "ds2 = g2[0] *(g2[4] *math.log(Tm/g2[2]) +g2[3] /778.0 *math.log(vm/v2))\n", "ds3 = g3[0] *(g3[4] *math.log(Tm/g3[2]) +g3[3] /778.0 *math.log(vm/v3))\n", "ds = ds1+ds2+ds3\n", "\n", "#result\n", "print \"Pressure = \", round(Pm, 1), \"lb/in^2\"\n", "print \"Temperature = \", round(Tm), \"R\"\n", "print \"Entropy change = \", round(ds, 4), \"B/R\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Pressure = 25.2 lb/in^2\n", "Temperature = 630.0 R\n", "Entropy change = 0.0914 B/R\n" ] } ], "prompt_number": 26 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 12.13, page no. 254" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "vdot1 = 8500.0 #cfm of air\n", "v1 = 12.775 #from chart\n", "wdot = vdot1/v1\n", "\n", "h2 = 20.3 #from chart\n", "h1 = 13.85 #from chart\n", "h4 = 29.0 #from chart\n", "h3 = 20.3 #from chart\n", "\n", "#Part a\n", "Q12 = h2 - h1\n", "Q12 = wdot*Q12\n", "print \"Capacity of preheater: \", round(Q12, 2), \"B/min\"\n", "\n", "#Part b\n", "Q34 = h4 - h3\n", "Q34 = wdot*Q34\n", "print \"Capacity of reheater: \", round(Q34, 2), \"B/min\"\n", "\n", "#Part c\n", "\n", "w2 = 20.0/7000.0 #from chart\n", "w3 = 54.0/7000.0 #from chart\n", "W = w3 - w2\n", "W = wdot*W\n", "print \"Rate of water addition: \", round(W, 2), \"lbm/min\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Capacity of preheater: 4291.59 B/min\n", "Capacity of reheater: 5788.65 B/min\n", "Rate of water addition: 3.23 lbm/min\n" ] } ], "prompt_number": 3 } ], "metadata": {} } ] }