{
"metadata": {
"name": "",
"signature": "sha256:20bf663c37cc88094e4d6e0d7e23e0cfc96b3cd4eb305559eda1ce27188b9a4a"
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"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 9 : Thermal radiation basic\n",
"relations"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 9.1 Page No : 378"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math \n",
"\n",
"# Variables\n",
"T = 5527;\t\t\t#Temperature of black body in degree C\n",
"D = (1.39*10**6);\t\t\t#Diameter of the sun in km\n",
"L = (1.5*10**8);\t\t\t#Distance between the earth and sun in km\n",
"\n",
"# Calculations\n",
"q = (5.67*10**-8*(T+273)**4*D**2)/(4*L**2);\t\t\t#Rate of solar radiation in W/m**2\n",
"\n",
"# Results\n",
"print 'Rate of solar radiation on a plane normal to sun rays is %3.0f W/m**2'%(q)\n",
"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Rate of solar radiation on a plane normal to sun rays is 1377 W/m**2\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 9.2 Page No : 383"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Variables\n",
"T = (727+273);\t\t\t#Temperature of black body in K\n",
"l1 = 1;\t\t\t#Wavelength in micro meter\n",
"l2 = 5;\t\t\t#Wavelength in micro meter\n",
"F1 = 0.0003;\t\t\t#From Table 9.2 on page no. 385\n",
"F2 = 0.6337;\t\t\t#From Table 9.2 on page no. 385\n",
"\n",
"# Calculations\n",
"a = (5.67*10**-8*T**4)/1000;\t\t\t#Heat transfer in kW/m**2\n",
"F = (F2-F1)*a;\t\t\t#Fraction of thermal radiation emitted by the surface in kW/m**2\n",
"\n",
"# Results\n",
"print 'Fraction of thermal radiation emitted by the surface is %3.1f kW/m**2'%(F)\n",
"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Fraction of thermal radiation emitted by the surface is 35.9 kW/m**2\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 9.3 Page No : 384"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Variables\n",
"t = 0.8;\t\t\t#Transmittivity of glass in the region except in the wave length region [0.4,3]\n",
"T = 5555;\t\t\t#Temperature of black body in K\n",
"\n",
"# Calculations\n",
"ao = 0;\t\t\t#a0 in micro K\n",
"a1 = (0.4*T);\t\t\t#a1 for the wavelength 0.4 micro meter in micro K\n",
"a2 = (3*T);\t\t\t#a1 for the wavelength 3 micro meter in micro K\n",
"F0 = 0;\t\t\t#From Table 9.2 on page no.385\n",
"F1 = 0.10503;\t\t\t#From Table 9.2 on page no.385\n",
"F2 = 0.97644;\t\t\t#From Table 9.2 on page no.385\n",
"t1 = t*(F2-F1);\t\t\t#Average hemispherical transmittivity of glass \n",
"\n",
"# Results\n",
"print 'Average hemispherical transmittivity of glass is %3.2f'%(t1)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Average hemispherical transmittivity of glass is 0.70\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 9.4 Page No : 386"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Variables\n",
"l = 0.5;\t\t\t#Wavelength at maximum intensity of radiation in micro meter\n",
"C3 = 0.289*10**-2 #mK\n",
"\n",
"# Calculations\n",
"T = C3/(l*10**-6);\t\t\t#Temperature according to Wien's print lacement law in degree C\n",
"E = (5.67*10**-8*T**4)/10**6;\t\t\t#Emissive power umath.sing Stefan-Boltzmann law in MW/m**2\n",
"\n",
"# Results\n",
"print 'Surface temperature is %3.0f K Emissive power is %3.1f MW/m**2'%(T,E)\n",
"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Surface temperature is 5780 K Emissive power is 63.3 MW/m**2\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 9.5 Page No : 389"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Variables\n",
"Ts = (827+273);\t\t\t#Surface temperature in degree C\n",
"E = (1.37*10**10);\t\t\t#Emmisive power in W/m**3\n",
"\n",
"# Calculations\n",
"Eblmax = (1.307*10**-5*Ts**5);\t\t\t#Maximum emissive power in W/m**3\n",
"e = (E/Eblmax);\t\t\t#Emissivity of the body \n",
"lmax = ((0.289*10**-2)/Ts)/10**-6;\t\t\t#Wavelength correspoing to the maximum spectral intensity of radiation in micro meter\n",
"\n",
"# Results\n",
"print 'Wavelength corresponding to the maximum spectral intensity of radiation is %3.2f micro meter'%(lmax)\n",
"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Wavelength corresponding to the maximum spectral intensity of radiation is 2.63 micro meter\n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 9.6 Page No : 389"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"# Variables\n",
"T = (1400+273);\t\t\t#Temperature of the body in K\n",
"l = 0.65;\t\t\t#Wavelength in micro meter\n",
"e = 0.6;\t\t\t#Emissivity\n",
"\n",
"# Calculations\n",
"T = (1./((1./T)-((l*10**-6*math.log(1./e))/(1.439*10**-2))));\t\t\t#Temperature of the body in K\n",
"Tb = (T-273);\t\t\t#Temperature of the body in degree C\n",
"\n",
"# Results\n",
"print 'Temperature of the body is %3.0f degree C'%(Tb)\n",
"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Temperature of the body is 1467 degree C\n"
]
}
],
"prompt_number": 7
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 9.7 Page No : 391"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Variables\n",
"Ts = (37+273);\t\t\t#Temperature of metallic bar in K\n",
"T = 1100;\t\t\t#Interior temperature in K\n",
"a = 0.52;\t\t\t#Absorptivity at 1100 K\n",
"e = 0.8;\t\t\t#Emissivity at 310 K\n",
"\n",
"# Calculations\n",
"Q = (a*5.67*10**-8*T**4)/1000;\t\t\t#Rate of absorption in kW/m**2\n",
"E = (e*5.67*10**-8*Ts**4)/1000;\t\t\t#Rate of emission in kW/m**2\n",
"\n",
"# Results\n",
"print 'Rate of absorption is %3.2f kW/m**2 \\n \\\n",
"Rate of emission is %3.2f kW/m**2'%(Q,E)\n",
"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Rate of absorption is 43.17 kW/m**2 \n",
" Rate of emission is 0.42 kW/m**2\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 9.8 Page No : 391"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Variables\n",
"e1 = 0.3\t\t\t#Emissivity of glass upto 3 micro meter\n",
"e2 = 0.9;\t\t\t#Emissivity of glass above 3 micro meter\n",
"t = 0.8;\t\t\t#Transmittivity of glass in the region except in the wave length region [0.4,3]\n",
"\n",
"# Calculations\n",
"E = (5.67*10**-8*5780**4)/10**6;\t\t\t#Emissive power in MW/m**2\n",
"F1 = 0.10503;\t\t\t#From Table 9.2 on page no.385\n",
"F2 = 0.97644;\t\t\t#From Table 9.2 on page no.385\n",
"I = (E*10**6*(F2-F1))/10**6;\t\t\t#Total incident radiation in MW/m**2\n",
"T = (t*I);\t\t\t#Total radiation transmitted in MW/m**2\n",
"t1 = (e1*I);\t\t\t#Absorbed radiation in MW/m**2 in wavelength [0.4,3] micro meter\n",
"t2 = (e1*E*F1);\t\t\t#Absorbed radiation in MW/m**2 in wavelength not in the range [0.4,3] micro meter\n",
"t3 = (e2*(1-F2)*E);\t\t\t#Absorbed radiation in MW/m**2 in wavelength greater than 3 micro meter\n",
"R = (t1+t2+t3);\t\t\t#Total radiation absorbed in MW/m**2\n",
"\n",
"# Results\n",
"print 'Total radiation transmitted is %3.2f MW/m**2 \\n \\\n",
"Total radiation absorbed is %3.2f MW/m**2'%(T,R)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Total radiation transmitted is 44.12 MW/m**2 \n",
" Total radiation absorbed is 19.88 MW/m**2\n"
]
}
],
"prompt_number": 9
}
],
"metadata": {}
}
]
}