{ "metadata": { "name": "" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 17 - Fluid Flow : Nozzles and Orifices" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 1a - Pg 299" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#calculate the exit area\n", "#initialization of varaibles\n", "import math\n", "w=1 #lb/sec\n", "v2=36.4\n", "h1=1279.1 #B/lb\n", "h2=1091.7 #B/lb\n", "V1=100 #fps\n", "#calculations\n", "a2=w*v2/(math.sqrt(2*32.2*778*(h1-h2) + V1*V1)) #sq ft\n", "a2=1.705 #sq in\n", "#results\n", "print '%s %.3f %s' %(\"Exit area =\",a2,\"sq. in\")\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Exit area = 1.705 sq. in\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 1b - Pg 300" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Calculate the throat area\n", "#initialization of varaibles\n", "import math\n", "w=1 #lb/sec\n", "k=1.3\n", "P=100 #psia\n", "#calculations\n", "Pratio=math.pow((2/(k+1)),(k/(k-1)))\n", "Pt=Pratio*P\n", "print '%s' %(\"From table 3,\")\n", "ht=1221.5 #B/lb\n", "vt=8.841 #cu ft/lb\n", "at=w*vt/1700.\n", "#results\n", "print '%s %.4f %s' %(\"Throat area =\",at,\"sq ft\")\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "From table 3,\n", "Throat area = 0.0052 sq ft\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 2 - Pg 309" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Calculate the Throat and exit areas for both frictionless and frictioned nozzles\n", "#initialization of varaibles\n", "import math\n", "k=1.3\n", "P=250 #psia\n", "h0=1263.4 #B/lb\n", "w=10000. #lb\n", "cv=0.949\n", "vts=3.415 #cu ft/lb\n", "#calculations\n", "Pratio=math.pow((2/(k+1)),(k/(k-1)))\n", "Pt=Pratio*P\n", "hts=1208.2 #B/lb\n", "h2s=891 #B/lb\n", "Vts=math.sqrt(2*32.2*778*(h0-hts))\n", "w=w/3600. #lb/sec\n", "at=w*vts/(Vts)\n", "V2=cv*math.sqrt(2*32.2*778*(h0-h2s))\n", "etan=cv*cv\n", "h2=928. #B/lb\n", "print '%s' %(\"From table 3,\")\n", "v2=276. #cu ft/lb\n", "a2=w*v2/V2\n", "a2s=0.17 #ft^2\n", "Cw=0.98\n", "at2=at/Cw\n", "#results\n", "print '%s %.5f %s' %(\"\\n Throat area =\",at,\"ft^2\")\n", "print '%s %.3f %s' %(\"\\n Exit area =\",a2,\"ft^2\")\n", "print '%s %.3f %s' %(\"\\n For frictionless nozzle =\",a2s,\"ft^2\")\n", "print '%s %.5f %s' %(\"\\n Changed throat area =\",at2,\"ft^2 and exit area is unchanged\")\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "From table 3,\n", "\n", " Throat area = 0.00570 ft^2\n", "\n", " Exit area = 0.187 ft^2\n", "\n", " For frictionless nozzle = 0.170 ft^2\n", "\n", " Changed throat area = 0.00582 ft^2 and exit area is unchanged\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 3a - Pg 310" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#calculate the Exit velocity, throat and exit areas\n", "#initialization of varaibles\n", "import math\n", "w=1 #lb/sec\n", "Pratio=0.53\n", "k=1.4\n", "T0=800. #R\n", "cp=0.24\n", "P0=150. #psia\n", "P2=15. #psia\n", "#calculations\n", "Pt=Pratio*P0\n", "Tratio=math.pow((Pratio),((k-1)/k))\n", "Tts=T0*Tratio\n", "Vts=math.sqrt(2*32.2*778*cp*(T0-Tts))\n", "vts=53.34*Tts/(Pt*144.)\n", "at=w*vts/(Vts)\n", "T2s=T0*math.pow((Pt/P0),((k-1)/k))\n", "T2=460. #R\n", "V2=math.sqrt(2*32.2*cp*778*(T0-T2))\n", "v2=53.34*T2/(144.*P2)\n", "a2=w*v2/V2\n", "#results\n", "print '%s %d %s' %(\"Exit velocity =\",Vts,\"fps\")\n", "print '%s %.5f %s' %(\"\\n Throat area =\",at,\"ft^2\")\n", "print '%s %.5f %s' %(\"\\n Exit area =\",a2,\"ft^2\")\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Exit velocity = 1263 fps\n", "\n", " Throat area = 0.00246 ft^2\n", "\n", " Exit area = 0.00562 ft^2\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 3b - Pg 310" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#calculate the Exit velocity, throat and exit areas\n", "#initialization of varaibles\n", "import math\n", "h0=191.81 #B/lb\n", "Pr0=5.526\n", "w=1 #lb/sec\n", "Pratio=0.53\n", "k=1.4\n", "T0=800. #R\n", "cp=0.24\n", "P0=150. #psia\n", "P2=15. #psia\n", "Pt=79.5 #psia\n", "#calculations\n", "Prt=Pratio*Pr0\n", "print '%s' %(\"From keenan and kaye steam tables,\")\n", "Pr=2.929\n", "Tts=668 #R\n", "hts=159.9 #B/lb\n", "Vts=math.sqrt(2*32.2*778*(h0-hts))\n", "vts=53.34*Tts/(Pt*144.)\n", "at=w*vts/(Vts)\n", "Pr2=P2*Pr0/P0\n", "T2s=415 #R\n", "h2s=99.13 #B/lb\n", "h2=110.25 #B/lb\n", "T2=462 #R\n", "V2=math.sqrt(2*32.2*778*(h0-h2))\n", "v2=53.34*T2/(144.*P2)\n", "a2=w*v2/V2\n", "#results\n", "print '%s %d %s' %(\"Exit velocity =\",Vts,\"fps\")\n", "print '%s %.5f %s' %(\"\\n Throat area =\",at,\"ft^2\")\n", "print '%s %.5f %s' %(\"\\n Exit area =\",a2,\"ft^2\")\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "From keenan and kaye steam tables,\n", "Exit velocity = 1264 fps\n", "\n", " Throat area = 0.00246 ft^2\n", "\n", " Exit area = 0.00564 ft^2\n" ] } ], "prompt_number": 5 } ], "metadata": {} } ] }