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{
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{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 19 : Two Stroke Engines"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 19.3 Page no : 334"
]
},
{
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"collapsed": false,
"input": [
"import math \n",
"\t\t\t\t\t\n",
"#Input data\n",
"d = 11.25\t\t\t\t\t#Bore in cm\n",
"l = 15.\t\t\t\t\t#Stroke in cm\n",
"r = 7.\t\t\t\t\t#Compression ratio\n",
"N = 1800.\t\t\t\t\t#Speed in r.p.m\n",
"a = 4.5\t\t\t\t\t#Air supply in kg/min\n",
"Ta = 72.+273\t\t\t\t\t#Temperature of air in K\n",
"af = 14.3\t\t\t\t\t#Air fuel ratio\n",
"ep = 1.\t\t\t\t\t#Exhaust pressure in kg/cm**2\n",
"R = 29.27\t\t\t\t\t#Characteristic gas constant in kg.m/kg.degree C\n",
"\n",
"\t\t\t\t\t\n",
"#Calculations\n",
"Vc = ((r/(r-1))*(3.14/4)*(d/100)**2*(l/100))\t\t\t\t\t#Swept volume in m**3\n",
"Wa = (Vc*N*ep*10**4)/(R*Ta)\t\t\t\t\t#Ideal air capacity in kg/min\n",
"sr = (a/Wa)\t\t\t\t\t#Scavenging ratio\n",
"sn = (1-math.exp(-sr))\t\t\t\t\t#Scavenging efficiency \n",
"nt = (sn/sr)\t\t\t\t\t#Trapping efficiency\n",
"\n",
"\t\t\t\t\t\n",
"#Output\n",
"print 'a) Ideal air capacity is %3.2f kg/min \\\n",
"\\nb) Scavenging ratio is %3.2f \\\n",
"\\nc) Scavenging efficiency is %3.3f \\\n",
"\\nd) Trapping efficiency is %3.2f'%(Wa,sr,sn,nt)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"a) Ideal air capacity is 3.10 kg/min \n",
"b) Scavenging ratio is 1.45 \n",
"c) Scavenging efficiency is 0.766 \n",
"d) Trapping efficiency is 0.53\n"
]
}
],
"prompt_number": 3
}
],
"metadata": {}
}
]
}
|
