{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "##Chapter 11: Compressible Flow" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "### Example 11.1 Page no 420" ] }, { "cell_type": "code", "execution_count": 1, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Total change in enthalpy for 10 kg air = 180.0 kcal\n" ] } ], "source": [ "# Example 11.1\n", "\n", "from math import *\n", "\n", "from __future__ import division\n", "\n", "# Given\n", "\n", "T1 = 273 + 15 # temperature in K\n", "\n", "T2 = 273 + 90 # temperature in K\n", "\n", "Cp = 0.24 # cp for air in kcal/kgK\n", "\n", "# Solution\n", "\n", "dh = Cp*(T2-T1) # enthalpy per kg of air\n", "\n", "H = 10*dh # total enthallpy of 10 kg air\n", "\n", "print \"Total change in enthalpy for 10 kg air = \",round(H,0),\"kcal\"" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "### Example 11.2 Page no 420" ] }, { "cell_type": "code", "execution_count": 3, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Total change in enthalpy of 10 Kg of air = -0.255 kcal/K\n" ] } ], "source": [ "# Example 11.2\n", "\n", "from math import *\n", "\n", "from __future__ import division\n", "\n", "# Given\n", "\n", "T1 = 273 + 15 # temperature in K\n", "\n", "T2 = 273 + 90 # temperature in K\n", "\n", "P1 = 40 + 101.3 # pressure in abs\n", "\n", "P2 = 360 + 101.3 # presure in abs\n", "\n", "Cv = 0.171 # Specific volume Coefficient of air\n", "\n", "k = 1.4 # gas constant\n", "\n", "# solution\n", "\n", "dS = Cv*log((T2/T1)**k*(P2/P1)**(1-k))\n", "\n", "S = 10*dS\n", "\n", "print \"Total change in enthalpy of 10 Kg of air =\",round(S,3),\"kcal/K\"" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "### Example 11.3 Page no 421" ] }, { "cell_type": "code", "execution_count": 4, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Final temperature if air = 320.2 F\n", "Total work done on 10 slugs = 330.0 Btu\n" ] } ], "source": [ "# Example 11.3\n", "\n", "from math import *\n", "\n", "from __future__ import division\n", "\n", "\n", "P1 = 10 # pressure in psia\n", "\n", "P2 = 30 # pressure in psia\n", "\n", "T1 = 460+110 # temperature in R\n", "\n", "k =1.4 # gas constant\n", "\n", "T2 = T1*(P2/P1)**((k-1)/k)\n", "\n", "t2 = T2-460 # final temperature of air\n", "\n", "print \"Final temperature if air = \",round(t2,1),\"F\"\n", "\n", "Cv = 0.157 # coefficient of air \n", "\n", "W = Cv*(T2-T1) # work done per unit mass of oxygen\n", "\n", "Tw = 10*W # total work done on 10 slugs\n", "\n", "print \"Total work done on 10 slugs = \",round(Tw,0),\"Btu\" \n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "### Example 11.4 Page no 426" ] }, { "cell_type": "code", "execution_count": 5, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Speed of sound in water = 1483.0 m/s\n", "Speed of sound in ethly alcohol = 1238.0 m/s\n", "Speed of sound in Air = 343.0 m/s\n" ] } ], "source": [ "# Example 11.4\n", "\n", "from math import *\n", "\n", "from __future__ import division\n", "\n", "# Given\n", "\n", "# for water\n", "\n", "S =1 # specific gravity\n", "\n", "rho = S*1000 # density in kg/m**3\n", "\n", "bta = 2.2*10**9 # Bulk modulus of elasticity\n", "\n", "# ethly alcohol\n", "\n", "S1 =0.79 # specific gravity\n", "\n", "rho2 = S1*1000 # density in kg/m**3\n", "\n", "bta2 = 1.21*10**9 # Bulk modulus of elasticity\n", "\n", "# for air\n", "\n", "k = 1.4 # gas constant for air\n", "\n", "R = 287 # universal gas constant\n", "\n", "T = 273+20 # temperature in K\n", "\n", "# Solution\n", "\n", "C1 = sqrt(bta/rho)\n", "\n", "C2 = sqrt(bta2/rho2)\n", "\n", "print \"Speed of sound in water =\",round(C1,0),\"m/s\"\n", "\n", "print \"Speed of sound in ethly alcohol =\",round(C2,0),\"m/s\"\n", "\n", "C3 = sqrt(k*R*T)\n", "\n", "print \"Speed of sound in Air =\",round(C3,0),\"m/s\"\n", "\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "### Example 11.5 Page no 431" ] }, { "cell_type": "code", "execution_count": 6, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "0.753305702898\n", "Pressure at downstream = 3.03 psia\n", "Temperature at downstream = 157.3 F\n", "Velocity downstream = 463.02 ft/s\n" ] } ], "source": [ "# Example 11.5\n", "\n", "from math import *\n", "\n", "from __future__ import division\n", "\n", "# Given\n", "\n", "P1 = 1.5 # pressure in psia\n", "\n", "T1 = 40 + 460 # temperature in R\n", "\n", "k = 1.4 # gas constant\n", "\n", "R = 1716 # universal gas constant in ft.lb/slug R\n", "\n", "V1 = 1500 # velocity in ft/s\n", "\n", "# Solution\n", "\n", "c1 = sqrt(k*R*T1)\n", "\n", "M1 = V1/c1\n", "\n", "M2 = sqrt((2+(k-1)*M1**2)/(2*k*M1**2-(k-1)))\n", "print M2\n", "\n", "P2 = P1*((1+k*M1**2)/(1+k*M2**2))\n", "\n", "print \"Pressure at downstream = \",round(P2,2),\"psia\"\n", "\n", "T2 = T1*((1+0.5*(k-1)*M1**2)/(1+0.5*(k-1)*M2**2))\n", "\n", "t2 = T2-460\n", "\n", "print \"Temperature at downstream = \",round(t2,1),\"F\"\n", "V2 = M2*sqrt(k*R*t2)\n", "\n", "print \"Velocity downstream = \",round(V2,2),\"ft/s\"\n" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": false }, "outputs": [], "source": [] } ], "metadata": { "kernelspec": { "display_name": "Python 2", "language": "python", "name": "python2" }, "language_info": { "codemirror_mode": { "name": "ipython", "version": 2 }, "file_extension": ".py", "mimetype": "text/x-python", "name": "python", "nbconvert_exporter": "python", "pygments_lexer": "ipython2", "version": "2.7.3" } }, "nbformat": 4, "nbformat_minor": 0 }