{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# Chapter 17:Compressible Fluid Flow" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex17.2:pg-717" ] }, { "cell_type": "code", "execution_count": 2, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " Example 17.2 \n", "\n", "\n", " Mass flow rate of air through diffuser is 59.4200292233 Kg/s\n", "\n", " Mach number of leaving air is 0.135\n", "\n", " Temperature of leaving air is 71.4290750078 degree celcius\n", "\n", " Pressure of leaving air is 0.260471799082 MPa \n", "\n", " Net thrust is 51.3284455434 kN\n" ] } ], "source": [ "import math\n", "P1 = 0.18 # Diffuser static pressure in MPa\n", "R = 0.287 # Gas constant\n", "T1 = 37 # Static temperature \n", "P0 = 0.1# Atmospheric pressure in MPa\n", "A1 = 0.11 # intake area in m**2\n", "V1 = 267 # Inlet velocity in m/s\n", "w = (P1*1e3/(R*(T1+273)))*A1*V1 # mass flow rate\n", "g = 1.4 # Heat capacity ratio\n", "c1 = math.sqrt(g*R*(T1+273)*1000) # velocity\n", "M1 = V1/c1 # Mach number\n", "A1A_ = 1.0570 # A1/A* A* = A_\n", "P1P01 = 0.68207 # pressure ratio\n", "T1T01 = 0.89644# Temperature ratio\n", "F1F_ = 1.0284# Impulse function ratio\n", "A2A1 = 0.44/0.11 # Area ratio\n", "A2A_ = A2A1*A1A_# Area ratio\n", "M2 = 0.135 # Mach number\n", "P2P02 = 0.987 # Pressure ratio\n", "T2T02 = 0.996 # Temperature ratio\n", "F2F_ = 3.46# Impulse function ratio\n", "P2P1 = P2P02/P1P01 # Pressure ratio\n", "T2T1 = T2T02/T1T01# Temperature ratio\n", "F2F1 = F2F_/F1F_ # Impulse function ratio\n", "P2 = P2P1*P1 # Outlet pressure\n", "T2 = T2T1*(T1+273) # Outlet temperature\n", "A2 = A2A1*A1 # Exit area\n", "F1 = P1*A1*(1+g*M1**2) # Impulse function\n", "F2 = F2F1*F1 # Impulse function\n", "Tint = F2-F1 # Internal thrust\n", "Text = P0*(A2-A1) # External thrust\n", "NT = Tint - Text # Net thrust\n", "\n", "print \"\\n Example 17.2 \\n\"\n", "print \"\\n Mass flow rate of air through diffuser is \",w ,\" Kg/s\"\n", "print \"\\n Mach number of leaving air is \",M2\n", "print \"\\n Temperature of leaving air is \",T2-273 ,\" degree celcius\"\n", "print \"\\n Pressure of leaving air is \",P2 ,\" MPa \"\n", "print \"\\n Net thrust is \",NT*1e3 ,\" kN\"\n", "\n", "#The answers vary due to round off error\n", "\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex17.3:pg-718" ] }, { "cell_type": "code", "execution_count": 6, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " Example 17.3\n", "\n", "\n", " When divergent section act as a nozzle\n", "\n", " Maximum flow rate of air is 1.06476372092 kg/s\n", "\n", " Static temperature is 183.204 K\n", "\n", " Static Pressure is 93.9 kPa\n", "\n", " Velocity at the exit from the nozzle is 596.077184351 m/s\n", "\n", "\n", " When divergent section act as a diffuser\n", "\n", " Maximum flow rate of air is 1.06476372092 kg/s\n", "\n", " Static temperature is 353.232 K\n", "\n", " Static Pressure is 936.0 kPa\n", "\n", " Velocity at the exit from the nozzle is 116.03411731 m/s\n" ] } ], "source": [ "import math\n", "M2 = 2.197 # Mach number\n", "P2P0 = 0.0939 # pressure ratio\n", "T2T0 = 0.5089 # Temperature ratio\n", "P0 = 1 # Stagnation pressure in MPa \n", "T0 = 360 # Stagnation temperature in K\n", "g = 1.4 # Heat capacity ratio\n", "R = 0.287 # Gas constant\n", "P2 = P2P0*P0*1e3 # Static Pressure\n", "T2 = T2T0*T0 # Static temperature\n", "c2 = math.sqrt(g*R*T2*1000)\n", "V2 = c2*M2 #velocity at the exit from the nozzle\n", "# for air\n", "P_P0 = 0.528 # pressure ratio\n", "T_T0 = 0.833 # Temperature ratio\n", "P_ = P_P0*P0*1e3 # Static Pressure\n", "T_ = T_T0*T0 #Static temperature\n", "rho_ = P_/(R*T_) # density\n", "V_ = math.sqrt(g*R*T_*1000) # Velocity at the exit from the nozzle \n", "At = 500e-06 # throat area\n", "w = At*V_*rho_# Maximum flow rate of air\n", "\n", "print \"\\n Example 17.3\\n\"\n", "print \"\\n When divergent section act as a nozzle\"\n", "print \"\\n Maximum flow rate of air is \",w ,\" kg/s\"\n", "print \"\\n Static temperature is \",T2 ,\" K\"\n", "print \"\\n Static Pressure is \",P2 ,\" kPa\"\n", "print \"\\n Velocity at the exit from the nozzle is \",V2 ,\" m/s\"\n", "#The answers vary due to round off error\n", "\n", "# Part (b)\n", "Mb = 0.308 # Mach number\n", "P2P0b = 0.936 # Pressure ratio\n", "T2T0b = 0.9812 # Temperature ratio\n", "P2b = P2P0b*P0*1e3#Static Pressure \n", "T2b = T2T0b*T0 # Static temperature\n", "c2b = math.sqrt(g*R*T2b*1000) # Velocity \n", "V2b = c2b*Mb #Velocity at the exit from the nozzle\n", "print \"\\n\\n When divergent section act as a diffuser\"\n", "print \"\\n Maximum flow rate of air is \",w ,\" kg/s\"\n", "print \"\\n Static temperature is \",T2b ,\" K\"\n", "print \"\\n Static Pressure is \",P2b ,\" kPa\"\n", "print \"\\n Velocity at the exit from the nozzle is \",V2b ,\" m/s\"\n", "\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex17.4:pg-720" ] }, { "cell_type": "code", "execution_count": 7, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " Example 17.4\n", "\n", "\n", " Mach number of the tunnel is 1.735\n" ] } ], "source": [ "import math\n", "Px = 16.0 # pressure in kPa\n", "Poy = 70.0 #pressure in kPa \n", "Mx = 1.735 # Mach number\n", "Pyx = 3.34 # Pressure ratio\n", "rho_yx = 2.25 # Density ratio\n", "Tyx = 1.483 # Temperature ratio\n", "Poyox = 0.84 # pressure ratio\n", "My = 0.631 # Mach number\n", "g = 1.4 # Ratio of heat capacities\n", "Tox = 573.0 # stagnation temperature in K \n", "Toy = Tox # temperature equivalence\n", "Tx = Tox/(1+((g-1)/2.0)*Mx**2) # temperature at x\n", "Ty = Tyx*Tx # temperature at y\n", "Pox = Poy/Poyox # total pressure \n", "# From table\n", "Mx = 1.735\n", "\n", "print \"\\n Example 17.4\\n\"\n", "print \"\\n Mach number of the tunnel is \",Mx\n", "\n", "\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex17.5:pg-721" ] }, { "cell_type": "code", "execution_count": 9, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " Example 17.5\n", "\n", "\n", " Exit Mach number is 0.402\n", "\n", " Exit pressure is 147.9260475 kPa\n", "\n", " Exit Stagnation pressure is 44.7195 kPa\n", "\n", " Entropy increase is 0.068726024552 kJ/kg K\n" ] } ], "source": [ "import math\n", "Ax = 18.75 # cross sectional area in divergent part in m**2\n", "A_ = 12.50 # throat area in m**2\n", "AA_ = 1.5 # Area ratio\n", "Pxox = 0.159 # pressure ratio from table\n", "R = 0.287 # Gas constant\n", "Pox = 0.21e03 # pressure in kPa\n", "Px = Pxox*Pox # pressure calculation\n", "# from the gas table on normal shock\n", "Mx = 1.86 \n", "My = 0.604 \n", "Pyx = 3.87 \n", "Poyx = 4.95 \n", "Poyox = 0.786\n", "Py = Pyx*Px\n", "Poy = Poyx*Px\n", "My = 0.604\n", "Ay_ = 1.183\n", "A2 = 25 \n", "Ay = 18.75\n", "A2_ = (A2/Ay)*Ay_\n", "# From isentropic table \n", "M2 = 0.402\n", "P2oy = 0.895\n", "P2 = P2oy*Poy\n", "syx = -R*math.log(Poy/Pox) # sy-sx\n", "\n", "print \"\\n Example 17.5\\n\"\n", "print \"\\n Exit Mach number is \",M2\n", "print \"\\n Exit pressure is \",P2 ,\" kPa\"\n", "print \"\\n Exit Stagnation pressure is \",Pox-Poy ,\" kPa\"\n", "print \"\\n Entropy increase is \",syx ,\" kJ/kg K\"\n", "#The answers vary due to round off error\n", "\n" ] } ], "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": "2.7.11" } }, "nbformat": 4, "nbformat_minor": 0 }