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{
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"name": "",
"signature": "sha256:b620865a516deeb75cd703005b53698c7a7013658cab02400acc0bf08c43a5d1"
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"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 17 - Internal-combustion engines"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 1 - Pg 358"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#calculate the indicated efficiency, brake thermal efficiency in both cases\n",
"#Initalization of variables\n",
"hp1=2000. #bhp\n",
"m=792. #lb/hr\n",
"ex=0.5\n",
"hp2=210.\n",
"hv=18900. #Btu/lb\n",
"etth=51.3\n",
"#calculations\n",
"ihp=hp1+hp2\n",
"ietat= ihp*2544/(m*hv) *100\n",
"betat=ietat*hp1/ihp\n",
"betat2=hp1*2544/(m*hv) *100\n",
"ietae=ietat/etth *100\n",
"betae=betat/etth *100\n",
"brake= ietae*hp1/ihp\n",
"#results\n",
"print '%s %.1f %s' %(\"Indicated efficiency =\",ietat,\"percent\")\n",
"print '%s %.1f %s' %(\"\\n Brake thermal efficiency =\",betat,\" percent\")\n",
"print '%s %.1f %s' %(\"\\n In case 2, Brake thermal efficiency =\",betat2,\"percent\")\n",
"print '%s %.1f %s' %(\"\\n Indicated thermal efficiency =\",ietae,\" percent\")\n",
"print '%s %.1f %s' %(\"\\n Brake engine efficiency =\",betae,\" percent\")\n",
"print '%s %.1f %s' %(\"\\n In case 2, Brake engine efficiency =\",brake,\"percent\")\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Indicated efficiency = 37.6 percent\n",
"\n",
" Brake thermal efficiency = 34.0 percent\n",
"\n",
" In case 2, Brake thermal efficiency = 34.0 percent\n",
"\n",
" Indicated thermal efficiency = 73.2 percent\n",
"\n",
" Brake engine efficiency = 66.3 percent\n",
"\n",
" In case 2, Brake engine efficiency = 66.3 percent\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2 - Pg 361"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#calculate the indicated mep\n",
"#Initalization of variables\n",
"J=778.\n",
"o2=12.5\n",
"theo=0.95\n",
"N=56.5\n",
"R0=1545.\n",
"T=540. #R\n",
"p=14. #psia\n",
"LHV=2368089. #Btu/lb\n",
"ther=39.4\n",
"iep=0.78\n",
"ve=0.8\n",
"#calculations\n",
"Ar=o2/0.21 *theo\n",
"vol=N*R0*T/(144*p)\n",
"hv=(LHV -17730)/LHV\n",
"ithep=iep*ther\n",
"pd=ithep/100 *ve *100.5\n",
"mep=J*pd\n",
"#results\n",
"print '%s %d %s' %(\"Indicated mep =\",mep,\"lb/sq ft\")\n",
"print '%s' %(\"The answer might differ from textbook due to rounding off error\")"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Indicated mep = 19223 lb/sq ft\n",
"The answer might differ from textbook due to rounding off error\n"
]
}
],
"prompt_number": 1
}
],
"metadata": {}
}
]
}
|
