{
"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
}