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diff --git a/Thermodynamics_for_Engineers/Chapter_18.ipynb b/Thermodynamics_for_Engineers/Chapter_18.ipynb new file mode 100755 index 00000000..0ec1053a --- /dev/null +++ b/Thermodynamics_for_Engineers/Chapter_18.ipynb @@ -0,0 +1,343 @@ +{
+ "metadata": {
+ "name": "",
+ "signature": "sha256:f0820b11a700821a3d31d338557194301893d84e5100c7860794ac7f11c2fe67"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+ {
+ "cells": [
+ {
+ "cell_type": "heading",
+ "level": 1,
+ "metadata": {},
+ "source": [
+ "Chapter 18 - Gas Compressors "
+ ]
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 1 - Pg 374"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#calculate the theoretical horse power\n",
+ "#Initalization of variables\n",
+ "import math\n",
+ "q=200. #cfm\n",
+ "p2=90. #psia\n",
+ "p1=14.5 #psia\n",
+ "n=1.36\n",
+ "#calculations\n",
+ "hpp=n/(n-1) *144.*p1*q/33000. *(-1+math.pow(p2/p1, (n-1)/n))\n",
+ "#results\n",
+ "print '%s %.1f %s' %(\"Theoretical horse power required =\",hpp,\" hp\")\n",
+ "print '%s' %(\"The answer given in textbook is wrong. Please verify with a calculator\")\n"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "Theoretical horse power required = 29.7 hp\n",
+ "The answer given in textbook is wrong. Please verify with a calculator\n"
+ ]
+ }
+ ],
+ "prompt_number": 1
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 2 - Pg 377"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#calcualte the indicated hp and shaft hp\n",
+ "#Initalization of variables\n",
+ "import math\n",
+ "q=350. #cfm\n",
+ "eff=0.78\n",
+ "x=0.95\n",
+ "p2=120. #psia\n",
+ "p1=14.3 #psia\n",
+ "#calculations\n",
+ "cal=p1*144*q/550 *math.log(p2/p1) /100.\n",
+ "ihp= cal/eff\n",
+ "shp=ihp/x\n",
+ "#results\n",
+ "print '%s %.1f %s' %(\"Indicated hp =\",ihp,\"hp\")\n",
+ "print '%s %.1f %s' %(\"\\n Shaft hp =\",shp,\"hp\")\n"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "Indicated hp = 35.7 hp\n",
+ "\n",
+ " Shaft hp = 37.6 hp\n"
+ ]
+ }
+ ],
+ "prompt_number": 2
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 3 - Pg 380"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#calculate the theoretical hp and piston displacement and max. temperature\n",
+ "#Initalization of variables\n",
+ "import math\n",
+ "n=1.35\n",
+ "p1=14.2\n",
+ "q=400. #cfm\n",
+ "p2=200. #psia\n",
+ "p1=14.2 #psia\n",
+ "ve=0.75\n",
+ "t1=530. #R\n",
+ "#calculations\n",
+ "thp=-n/(n-1) *144 *p1*q/33000 *(1- math.pow(p2/p1,(n-1)/n))\n",
+ "pd=q/ve\n",
+ "Tmax=t1*math.pow(p2/p1,(n-1)/n)\n",
+ "#results\n",
+ "print '%s %.1f %s' %(\"Theoretical hp =\",thp,\" hp\")\n",
+ "print '%s %d %s' %(\"\\n Piston displacement =\",pd,\"cfm\")\n",
+ "print '%s %d %s' %(\"\\n Max. Temperature =\",Tmax,\"R\")\n"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "Theoretical hp = 94.2 hp\n",
+ "\n",
+ " Piston displacement = 533 cfm\n",
+ "\n",
+ " Max. Temperature = 1052 R\n"
+ ]
+ }
+ ],
+ "prompt_number": 3
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 4 - Pg 381"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#calculate the theoretical hp and piston displacement and max. temperature\n",
+ "#Initalization of variables\n",
+ "import math\n",
+ "n=1.35\n",
+ "p1=14.2 #psia\n",
+ "p3=200. #psia\n",
+ "q=400. #cfm\n",
+ "ve=0.78\n",
+ "t1=530. #R\n",
+ "#calculations\n",
+ "p2=math.sqrt(p3*p1) #psia\n",
+ "thp=-2*n/(n-1) *144 *p1*q/33000 *(1- math.pow(p2/p1,(n-1)/n))\n",
+ "pd=q/ve\n",
+ "pd2=q*p1/p2 /ve\n",
+ "Tmax=t1*math.pow(p2/p1,(n-1)/n)\n",
+ "#results\n",
+ "print '%s %.1f %s' %(\"Theoretical hp =\",thp,\" hp\")\n",
+ "print '%s %.1f %s' %(\"\\n For low pressure case, Piston displacement =\",pd,\"cfm\")\n",
+ "print '%s %.1f %s' %(\"\\n For high pressure case, Piston displacement =\",pd2,\"cfm\")\n",
+ "print '%s %.1f %s' %(\"\\n Max. Temperature =\",Tmax,\" R\")\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": [
+ "Theoretical hp = 78.2 hp\n",
+ "\n",
+ " For low pressure case, Piston displacement = 512.8 cfm\n",
+ "\n",
+ " For high pressure case, Piston displacement = 136.6 cfm\n",
+ "\n",
+ " Max. Temperature = 746.8 R\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 386"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#calculate the theoretical pressure at exit\n",
+ "#Initalization of variables\n",
+ "import math\n",
+ "dia=2 #ft\n",
+ "rpm=6000. #rpm\n",
+ "p=14.2 #psia\n",
+ "t=75. #F\n",
+ "g=32.17\n",
+ "n=1.4\n",
+ "R=53.35\n",
+ "#calculations\n",
+ "v=2*math.pi*rpm/60.\n",
+ "wbym=v*v /g\n",
+ "T=t+460.\n",
+ "pr=1+ wbym*(n-1)/n /(R*T) \n",
+ "pr2=math.pow(pr,(n/(n-1)))\n",
+ "p2=pr2*p\n",
+ "#results\n",
+ "print '%s %.1f %s' %(\"Theoretical pressure at exit =\",p2,\" psia\")\n"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "Theoretical pressure at exit = 21.3 psia\n"
+ ]
+ }
+ ],
+ "prompt_number": 5
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 6 - Pg 391"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#calculate the velocity of air\n",
+ "#Initalization of variables\n",
+ "import math\n",
+ "pa=14.7 #psia\n",
+ "p1=12. #psia\n",
+ "t1=560. #R\n",
+ "n=1.4 #gamma\n",
+ "J=778. #constant conversion\n",
+ "g=32.2 #ft/s^2\n",
+ "cp=0.24 #heat capacity\n",
+ "eff=0.7 #efficiency\n",
+ "m1=1.8 \n",
+ "m3=1. \n",
+ "#calculations\n",
+ "t5=t1*math.pow(pa/p1,((n-1)/n))\n",
+ "v4=math.sqrt(2*g*J*cp*(t5-t1)/eff) \n",
+ "v3=(m1+m3)/m1 *v4\n",
+ "#results\n",
+ "print '%s %.1f %s' %(\"Velocity of air =\",v3,\" ft/s\")\n",
+ "print '%s' %(\"The answer given in textbook is wrong. Please verify with a calculator\")"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "Velocity of air = 1178.8 ft/s\n",
+ "The answer given in textbook is wrong. Please verify with a calculator\n"
+ ]
+ }
+ ],
+ "prompt_number": 1
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 7 - Pg 391"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#calculate the pressure required\n",
+ "#Initalization of variables\n",
+ "import math\n",
+ "v2=1180. #ft/s\n",
+ "etan=0.95\n",
+ "cp=0.24\n",
+ "n=1.4\n",
+ "p2=12.\n",
+ "#calculations\n",
+ "dh=v2*v2 /(etan*223.8*223.8)\n",
+ "dt=dh/cp\n",
+ "t2d=560. #R\n",
+ "t1=t2d+ etan*dt\n",
+ "t2=554. #R\n",
+ "pr=math.pow(t1/t2,(n/(n-1)))\n",
+ "p1=p2*pr\n",
+ "#results\n",
+ "print '%s %.2f %s' %(\"Pressure required =\",p1,\"psia\")\n"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "Pressure required = 24.06 psia\n"
+ ]
+ }
+ ],
+ "prompt_number": 7
+ }
+ ],
+ "metadata": {}
+ }
+ ]
+}
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