{ "metadata": { "name": "", "signature": "sha256:6b7b3e2ab4fd666f452b57925a83681d6f79a5b142e4777bdab089506c8a15bb" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 21 - Steam Turbines" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 1 - Pg 456" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#calculate the flow rate\n", "#Initalization of variables\n", "import math\n", "p2=190. #psia\n", "p1=110. #psia\n", "v1=2.456 \n", "k=1.3\n", "J=778.\n", "A2=1.2 #in^2\n", "#calculations\n", "v2=v1*math.pow(p2/p1,(1/k))\n", "dh=k/(k-1) *144/J *(p2*v1-p1*v2)\n", "Vex=223.8*math.sqrt(dh)\n", "m=A2*Vex/(144.*v2)\n", "#results\n", "print '%s %.2f %s' %(\"Rate of flow =\",m,\"lb/sec\")\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Rate of flow = 3.32 lb/sec\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 2 - Pg 458" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#calculate the rate of flow\n", "#Initalization of variables\n", "import math\n", "h1=1205.8 #Btu/lb\n", "s2=1.5594\n", "sf=1.5948\n", "sfg=1.1117\n", "hf=1188.9 #Btu/lb\n", "hfg=883.2 #Btu/lb\n", "vf=4.049\n", "vfg=vf-0.018\n", "k=1.3\n", "J=778\n", "A2=1.2 #in^2\n", "#calculations\n", "x2=-(s2-sf)/sfg\n", "h2=hf-x2*hfg\n", "v2=vf-x2*vfg\n", "dh=h1-h2\n", "Vex=223.8*math.sqrt(dh)\n", "m=A2*Vex/(144*v2)\n", "#results\n", "print '%s %.2f %s' %(\"Rate of flow =\",m,\"lb/sec\")\n", "\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Rate of flow = 3.19 lb/sec\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 3 - Pg 462" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#calculate the blade work, angle and efficiency\n", "#Initalization of variables\n", "import math\n", "alp=14*math.pi/180. #degrees\n", "vb=900. #ft/s\n", "v1=2200. #ft/s\n", "g=32.17 #ft/s^2\n", "#calculations\n", "vrc=v1*math.cos(alp) - vb\n", "W=(2*vrc)/g *vb\n", "eta=W/(v1*v1/ (2*g)) *100.\n", "bet=math.atan(v1*math.sin(alp) /vrc)*180/math.pi\n", "#results\n", "print '%s %d %s' %(\"Blade work =\",W,\" ft-lb/lb\")\n", "print '%s %.1f %s' %(\"\\n Efficiency =\",eta,\" percent\")\n", "print '%s %.1f %s' %(\"\\n Blade angle =\",bet,\" degrees\")\n", "print '%s' %('The answers are a bit different due to rounding off error')\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Blade work = 69082 ft-lb/lb\n", "\n", " Efficiency = 91.8 percent\n", "\n", " Blade angle = 23.3 degrees\n", "The answers are a bit different due to rounding off error\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 4 - Pg 463" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#calculate the blade work and efficiency\n", "#Initalization of variables\n", "import math\n", "v1=1234. #ft/s\n", "v2=532. #ft/s \n", "kb=0.92\n", "alp=20. #degrees\n", "ve=900. #ft/s\n", "r=2200. #ft/s\n", "g=32.17 #ft/s^2\n", "#calculations\n", "vr=math.sqrt(v1*v1 +v2*v2)\n", "vr2=vr*kb\n", "vrc=vr2*math.cos(alp*math.pi/180.)\n", "W=(v1+vrc)*ve/g\n", "eta=W/(r*r /(2*g)) *100.\n", "#results\n", "print '%s %d %s' %(\"Blade work =\",W,\"ft-lb/lb\")\n", "print '%s %.1f %s' %(\"\\n Efficiency =\",eta,\" percent\")\n", "print '%s' %('The answers are a bit different due to rounding off error')\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Blade work = 67023 ft-lb/lb\n", "\n", " Efficiency = 89.1 percent\n", "The answers are a bit different due to rounding off error\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 5 - Pg 464" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#calculate the blade reheat in both cases\n", "#Initalization of variables\n", "import math\n", "v1=1234.\n", "v2=532.\n", "kb=0.92\n", "alp=20*math.pi/180. #degrees\n", "ve=900.\n", "r=2200. #ft/s\n", "g=32.17 #ft/s^2\n", "J=778.\n", "w=67000.\n", "#calculations\n", "vr=math.sqrt(v1*v1 +v2*v2)\n", "vr2=vr*kb\n", "vrc=vr2*math.cos(alp)\n", "reheat=(vr*vr - vr2*vr2 )/(2*g*J)\n", "v22=math.sqrt((vrc-ve)*(vrc-ve) +(vr2*math.sin(alp))*(vr2*math.sin(alp)))\n", "ein=r*r /(2*g*J)\n", "eout=w/J + v22*v22 /(2*g*J)\n", "re2=ein-eout\n", "#results\n", "print '%s %.2f %s' %(\"\\n In case 1, Blade reheat =\",reheat,\"Btu/lb\")\n", "print '%s %.1f %s' %(\"\\n In case 2, Blade reheat =\",re2,\" Btu/lb\")\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "\n", " In case 1, Blade reheat = 5.54 Btu/lb\n", "\n", " In case 2, Blade reheat = 5.6 Btu/lb\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6 - Pg 467" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#calculate the intermediate pressure\n", "#Initalization of variables\n", "h1=1416.4\n", "s1=1.6842\n", "sf=1.7319\n", "sfg=1.3962\n", "fac=1.05\n", "x2=0.7\n", "#calculations\n", "x6=-(s1-sf)/sfg\n", "h6=1156.3 - x6*960.1\n", "dh6=h1-h6\n", "drop= fac*h6/2\n", "h2=h1-drop\n", "first=(1-x2)*drop\n", "h3=1264.1 +first\n", "h4=1157 #Btu/lb\n", "fac2=(drop+153)/dh6\n", "print '%s' %(\"From air charts,\")\n", "p2=107 #psia\n", "#results\n", "print '%s %d %s' %(\"Intermediate pressure =\",p2,\"psia\")\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "From air charts,\n", "Intermediate pressure = 107 psia\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 7 - Pg 469" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#calculate the shaft ouput and engine efficiency\n", "#Initalization of variables\n", "import math\n", "reh=1.047\n", "dh6=292.8\n", "x2=0.7\n", "flow=98000 #lb/hr\n", "loss=200 #hp\n", "#calculations\n", "intwork=reh*dh6*x2\n", "inthp=intwork*flow/2544\n", "sout=inthp-loss\n", "swork=sout*2544/flow\n", "seff=swork/290.1 *100\n", "#results\n", "print '%s %d %s' %(\"Shaft output =\",sout,\"hp\")\n", "print '%s %.1f %s' %(\"\\n Shaft engine efficiency =\",seff,\"percent\")\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Shaft output = 8066 hp\n", "\n", " Shaft engine efficiency = 72.2 percent\n" ] } ], "prompt_number": 7 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 8 - Pg 469" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#calculate the exit temperature and pressure\n", "#Initalization of variables\n", "h1=1416.4 #Btu/lb\n", "h2=214.5 #Btu/lb\n", "#calculations\n", "hexa=h1-h2\n", "print '%s' %(\"From Air tables,\")\n", "pe=20 #psia\n", "te=321.5 #F\n", "#results\n", "print '%s %d %s' %(\"Exit Pressure =\",pe,\"psia\")\n", "print '%s %.1f %s' %(\"\\n Exit temperature =\",te,\" F\")\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "From Air tables,\n", "Exit Pressure = 20 psia\n", "\n", " Exit temperature = 321.5 F\n" ] } ], "prompt_number": 8 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 9 - Pg 470" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#calculate the steam rate required\n", "#Initalization of variables\n", "flow=98000. #lb/hr\n", "loss=200. #hp\n", "x= 0.11 #percent\n", "shp=3000. #hp\n", "#calculations\n", "sflow = x*flow\n", "sflow2= sflow + (flow-sflow)*shp/8060.\n", "srate=sflow2/shp\n", "#results\n", "print '%s %.2f %s' %(\"Steam rate required =\",srate,\" lb/hp-hr\")\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Steam rate required = 14.41 lb/hp-hr\n" ] } ], "prompt_number": 9 } ], "metadata": {} } ] }