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{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Chapter 8 Second and third law topics"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Ex:8.1 Pg:255"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"dp by ds at constant volume = 275 F/ft**3/lbm\n",
"The answer is a bit different due to rounding off error in textbook\n"
]
}
],
"source": [
"#Initialization of variables\n",
"P=500 #psia\n",
"T=700 #F\n",
"J=778\n",
"#calculations\n",
"dpds=1490 *144/J\n",
"#results\n",
"print \"dp by ds at constant volume = %d F/ft**3/lbm\"%(dpds)\n",
"print \"The answer is a bit different due to rounding off error in textbook\""
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Ex:8.2 Pg:256"
]
},
{
"cell_type": "code",
"execution_count": 3,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Thermal efficiency = 66.5 percent\n"
]
}
],
"source": [
"from __future__ import division\n",
"from math import log\n",
"#Initialization of variables\n",
"cp=0.25 #Btu/lbm R\n",
"T0=520 #R\n",
"T1=3460 #R\n",
"#calculations\n",
"dq=cp*(T0-T1)\n",
"ds=cp*log(T0/T1)\n",
"dE=dq-T0*ds\n",
"eta=dE/dq\n",
"#results\n",
"print \"Thermal efficiency = %.1f percent\"%(eta*100)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Ex:8.3 Pg:256"
]
},
{
"cell_type": "code",
"execution_count": 4,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Loss of available energy = -6774 Btu/lbm\n",
"The answer is a bit different due to rounding off error in textbook\n"
]
}
],
"source": [
"from __future__ import division\n",
"from math import log\n",
"#Initialization of variables\n",
"cp=0.25 #Btu/lbm R\n",
"T0=520 #R\n",
"T1=3460 #R\n",
"dG=21069 #Btu/lbm\n",
"dH=21502 #Btu/lbm\n",
"#calculations\n",
"dq=cp*(T0-T1)\n",
"ds=cp*log(T0/T1)\n",
"dE=dq-T0*ds\n",
"eta=dE/dq\n",
"dw=eta*dH\n",
"de=-dG+dw\n",
"#results\n",
"print \"Loss of available energy = %d Btu/lbm\"%(de)\n",
"print \"The answer is a bit different due to rounding off error in textbook\""
]
}
],
"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": "2.7.9"
}
},
"nbformat": 4,
"nbformat_minor": 0
}
|
