{
"metadata": {
"name": "",
"signature": "sha256:9c8ef7403d1e4089b03a877df55583eac7aa3f196537402cb7dc0697b6d5bbe7"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter8-Entropy"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example1 pg- 168"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#calculate and entropy of ice and environment and universe\n",
"##initialisation of variables\n",
"m= 2 ##kg\n",
"dh= 333.39 ##kg/h\n",
"T= 0 ##C\n",
"T1= 20 ##C\n",
"##CALCULATIONS\n",
"Q12= m*dh\n",
"dS= Q12/(273.15+T)\n",
"dSenvir= -Q12/(273.15+T1)\n",
"dStotal= dS+dSenvir\n",
"##RESULTS\n",
"print'%s %.3f %s'%(' entropy of ice =',dS,'kJ/K')\n",
"print'%s %.3f %s'%('entropy of environment =',dSenvir,'kJ/K')\n",
"print'%s %.3f %s'%('entropy of universe =',dStotal,'kJ/K')\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" entropy of ice = 2.441 kJ/K\n",
"entropy of environment = -2.275 kJ/K\n",
"entropy of universe = 0.167 kJ/K\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example2-pg169"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#calculate change in entropy in system and environment and entropy\n",
"##initialisation of variables\n",
"Q= 666.78 ##kJ\n",
"T= 0 ##C\n",
"Th= 20. ##C\n",
"##CALCULATIONS\n",
"Ssys= Q/(273.15+T)\n",
"Qh= Q*((273.15+Th)/(273.15+T))\n",
"Senvir= -Qh/(273.15+Th)\n",
"Stotal= Ssys+Senvir\n",
"##RESULTS\n",
"print'%s %.4f %s'%('change in entropy in sysytem =',Ssys,' kJ/K')\n",
"print'%s %.4f %s'%('change in entropy in environment =',Senvir,'kJ/K')\n",
"print'%s %.f %s'%('total change in entropy =',Stotal,'kJ/K')\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"change in entropy in sysytem = 2.4411 kJ/K\n",
"change in entropy in environment = -2.4411 kJ/K\n",
"total change in entropy = 0 kJ/K\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example3-pg171\n"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#calculate change in entropy\n",
"##initialisation of variables\n",
"S1= 6.2872 ##J/kg K\n",
"S2= 5.8712 ##J/kg K\n",
"m= 18 ##kg\n",
"##CALCULATIONS\n",
"S= m*(S1-S2)\n",
"##RESULTS\n",
"print'%s %.3f %s'%(' change in entropy =',S,'kJ/K')\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" change in entropy = 7.488 kJ/K\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example4-pg 171"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#calculate change in entropy\n",
"##initialisation of variables\n",
"S2= 5.8328 ##kJ/kg\n",
"S1= 5.8712 ##kJ/kg\n",
"##CALCULATIONS\n",
"S= S2-S1\n",
"##RESULTS\n",
"print'%s %.5f %s'%('change in entropy = ',S,'kJ/K')\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"change in entropy = -0.03840 kJ/K\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example5-pg172"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#calculate enthalpy and change in entropy\n",
"##initialisation of variables\n",
"m= 0.1 ##kg\n",
"p= 3 ##bar\n",
"p1= 10 ##bar\n",
"h1= 2964.3 ##kJ/kg\n",
"v1=0.2378\n",
"s2= 7.1619 ##kJ/k\n",
"s1= 6.9641 ##kJ/k\n",
"##CALCULATIONS\n",
"h2= h1+(p-p1)*math.pow(10,5)*v1*math.pow(10,-3)\n",
"S= m*(s2-s1)\n",
"##RESULTS\n",
"print'%s %.1f %s'%(' enthalpy =',h2,'kJ/kg')\n",
"print'%s %.5f %s'%('change in entropy =',S,'kJ/K')\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" enthalpy = 2797.8 kJ/kg\n",
"change in entropy = 0.01978 kJ/K\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example6-pg 174"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#calculate final pressure and change in entropy\n",
"import math\n",
"##initialisation of variables\n",
"p1= 5. ##bar\n",
"V1= 0.4 ##m^2\n",
"V2= 1.2 ##m^3\n",
"R= 8.314 ##J/mol K\n",
"M= 28.##gms\n",
"T1= 80.##C\n",
"##CALCULATIONS\n",
"p2= p1*(V1/V2)\n",
"S= R*math.log(V2/V1)/M\n",
"S1= S*p1*V1*100/((R/M)*(273.15+T1))\n",
"##RESULTS\n",
"print'%s %.3f %s'%(' final pressure =',p2,'bar')\n",
"print'%s %.4f %s'% ('change in entropy =',S1,'kJ/kg K')\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" final pressure = 1.667 bar\n",
"change in entropy = 0.6222 kJ/kg K\n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example7-pg 175"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#calculate heat and change in entropy of system and change in entropy of enironment\n",
"##initialisation of variables\n",
"R= 8.314 ##J/mol K\n",
"M= 29. ##gms\n",
"T= 400. ##K\n",
"p2= 1.6 ##bar\n",
"p1= 1. ##bar\n",
"Tenvir= 300. ##K\n",
"##CALCULATIONS\n",
"q= R*T*math.log(p2/p1)/M\n",
"S= -R*math.log(p2/p1)/M\n",
"Senvir= q/Tenvir\n",
"##RESULTS\n",
"print'%s %.1f %s'%('heat =',q,'kJ/kg')\n",
"print'%s %.4f %s'%('change in entropy of system=',S,'kJ/kg K')\n",
"print'%s %.4f %s'%('change in entropy of environment=',Senvir,'kJ/kg K')\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"heat = 53.9 kJ/kg\n",
"change in entropy of system= -0.1347 kJ/kg K\n",
"change in entropy of environment= 0.1797 kJ/kg K\n"
]
}
],
"prompt_number": 7
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex8-pg176"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"##initialisation of variables\n",
"m1= 5 ##kg\n",
"c1= 1.26 ##kJ/kg K\n",
"m2= 20 ##kg\n",
"c2= 4.19 ##kJ/kg K\n",
"T1= 95 ##C\n",
"T2= 25 ##C\n",
"##CALCULATIONS\n",
"T= (m1*c1*T1+m2*c2*T2)/(m1*c1+m2*c2)\n",
"S1= m1*c1*math.log((273.15+T)/(273.15+T1))\n",
"S2= m2*c2*math.log((273.15+T)/(273.15+T2))\n",
"S= S1+S2\n",
"##RESULTS\n",
"print'%s %.2f %s'% (' change in entropy of billet =',S1,' kJ/K')\n",
"print'%s %.2f %s'% (' change in entropy of water= ',S2,' kJ/kg K')\n",
"print'%s %.2f %s'% (' change in entropy of water=',S,' kJ/kg K')\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" change in entropy of billet = -1.23 kJ/K\n",
" change in entropy of water= 1.36 kJ/kg K\n",
" change in entropy of water= 0.14 kJ/kg K\n"
]
}
],
"prompt_number": 3
}
],
"metadata": {}
}
]
}