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{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 5 : Bubbles in Dense Beds"
]
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Example 1, Page 126\n"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"dt=60.0; #ID of tube in cm \n",
"dp=300; #Size of particles of bed in micrometers\n",
"umf=3; #Velocity at minimum fluidization condition in cm/s\n",
"ephsilonmf=0.5; #Void fraction of bed at minimum fluidization condition\n",
"db=5; #Diameter of bubble in cm\n",
"g=980; #Acceleration due to gravity in cm/s**2\n",
"\n",
"#CALCULATION\n",
"#Computation of rise velocity of bubble\n",
"if (db/dt)<0.125:\n",
" ubr=(0.711*((g*db)**0.5));#Rise velocity by Eqn.(3)\n",
"elif (db/dt)<0.6:\n",
" ubr=(0.711*((g*db)**0.5))*1.2*exp(-1.49*(db/dt));#Rise velocity by Eqn.(4) \n",
"\n",
"#Computation of cloud thickness\n",
"Rb=db/2.0; #Radius of bubble\n",
"uf=umf/ephsilonmf; #Velocity of emulsion gas\n",
"Rc=Rb*((ubr+(2*uf))/(ubr-uf))**(1/3.0);#Radius of cloud by Eqn.(6)\n",
"\n",
"#OUTPUT\n",
"print 'The rise velocity of the bubble=%.1f cm/s'%ubr\n",
"print 'The cloud thickness=%.2f cm'%(Rc-Rb)\n",
"print 'From Fig.8(page 124)comparing fw vs dp, for dp = %.0f micrometer, wake fraction = 0.24'%dp\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The rise velocity of the bubble=49.8 cm/s\n",
"The cloud thickness=0.30 cm\n",
"From Fig.8(page 124)comparing fw vs dp, for dp = 300 micrometer, wake fraction = 0.24\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Example 2, Page 132\n"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"import math\n",
"\n",
"#Variable declaration\n",
"uo=15; #Superificial gas velocity in cm/s\n",
"umf=1; #Velocity at minimum fluidization condition in cm/s\n",
"lor=2.0; #Pitch of perforated plate in cm\n",
"g=980; #Acceleration due to gravity in cm/s**2\n",
"#CALCULATION\n",
"#Case(a) For porous plate\n",
"dbo1=(2.78/g)*(uo-umf)**2;#Initial bubble size using Eqn.(19)\n",
"\n",
"#Case(b) For Perforated plate\n",
"Nor=(2/math.sqrt(3))*(1/lor)**2;#Number of orifices in cm**-2\n",
"dbo2=(1.30/(g**0.2))*((uo-umf)/Nor)**0.4;#Initial bubble size using Eqn.(15) assuming inital bubble size is smaller than hole spacing\n",
"\n",
"#OUTPUT\n",
"print 'Case(a) For porous plate'\n",
"print '\\tInitial bubble size=%.2fcm'%dbo1\n",
"print 'Case(b) For Perforated plate'\n",
"print '\\tInitial bubble size=%.2fcm'%dbo2\n",
"print '\\tSince %f<%f, the equation used is correct.'%(dbo2,lor)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Case(a) For porous plate\n",
"\tInitial bubble size=0.56cm\n",
"Case(b) For Perforated plate\n",
"\tInitial bubble size=1.55cm\n",
"\tSince 1.548765<2.000000, the equation used is correct.\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "code",
"collapsed": false,
"input": [],
"language": "python",
"metadata": {},
"outputs": []
}
],
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}
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