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{
"metadata": {
"name": "",
"signature": "sha256:8d95c094e950bc8cd1f4bbc97c09344d22cf81b1ba4d6101a144be7a5e1e83dc"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter13-thermodynamic relations"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example2-pg284"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#calculate entropy wrt pressures and volume wrt temerature\n",
"##initialisation of variables\n",
"S1= 6.539 ##kJ/kg K\n",
"S2= 6.7664 ##kJ/kg K\n",
"v1= 0.10976 ##m^3\n",
"v2= 0.08700 ##m^3\n",
"P= 3. ##Mpa\n",
"P1= 2. ##Mpa\n",
"T= 350. ##K\n",
"T1= 250. ##K\n",
"S3= 3.1741 ##kJ/kg K\n",
"S4= 3.2071 ##kJ/kg K\n",
"P2= 30. ##Mpa\n",
"P3= 20. ##Mpa\n",
"v3= 0.0014217 ##m^3\n",
"v4= 0.0012860 ##m^3\n",
"T2= 320. ##K\n",
"T3= 280. ##K\n",
"##CALCULATIONS\n",
"r= (S1-S2)/(P*10*10*10-P1*10*10*10)\n",
"r1= (v1-v2)/(T-T1)\n",
"R= (S3-S4)/(P2*10*10*10-P3*10*10*10)\n",
"R1= (v3-v4)/(T2-T3)\n",
"##RESULTS\n",
"print'%s %.7f %s'% ('entropy wrt pressre=',r,'kJ/kg K kpa')\n",
"print'%s %.e %s'% ('entropy wrt pressre=',R,'kJ/kg K kpa')\n",
"print'%s %.7f %s'% ('volume wrt temperature=',r1,'m^3/kg K ')\n",
"print'%s %.2e %s'% ('volume wrt temperature=',R1,'m^3/kg K ')\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"entropy wrt pressre= -0.0002274 kJ/kg K kpa\n",
"entropy wrt pressre= -3e-06 kJ/kg K kpa\n",
"volume wrt temperature= 0.0002276 m^3/kg K \n",
"volume wrt temperature= 3.39e-06 m^3/kg K \n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example3-pg286"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#saturation pressure\n",
"##initialisation of variables\n",
"hfg= 2406.7 ##kJ/kg\n",
"Psat40= 7.384 ##kPa\n",
"R= 8.314 ##J/mol K\n",
"T= 40. ##C\n",
"T1= 50. ##C\n",
"M= 18.##kg\n",
"##CALCULATIONS\n",
"Psat50= Psat40*math.e**((hfg*M/R)*((1/(273.15+T))-(1/(273.15+T1))))\n",
"##RESULTS\n",
"print'%s %.3f %s' %('Saturation pressure=',Psat50,'kPa')\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Saturation pressure= 12.357 kPa\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example4-pg287"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#calcualte lowest temprature\n",
"##initialisation of variables\n",
"W= 800. ##N\n",
"A= 0.4 ##cm^2\n",
"p= 0.611 ##Mpa\n",
"P1= 0.1 ##Mpa\n",
"T= 0.01 ##C\n",
"vs= 0.0010908 ##m^3/kg\n",
"hs= -333.40 ##kJ/kg\n",
"vf= 0.0010002 ##m^3/kg\n",
"hf= 0 ##kJ/kg\n",
"vg= 206.14 ##m^3/kg\n",
"hg= 2501.4 ##kJ/kg\n",
"##CALCULATIONS\n",
"P2= P1+(W/A)*math.pow(10,(4-6))\n",
"dT= (273.15++T)*(vf-vs)*(P2*10*10*10-p)/(0-hs)\n",
"Tmin= dT+T\n",
"##RESULTS\n",
"print'%s %.2f %s'% ('lowest temperature=',Tmin,'C')\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"lowest temperature= -1.48 C\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example7-pg292"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#calculate volume exapansion coefficent and isothermal compressibilitiy and isotherma modulus of elasticity\n",
"##initialisation of variables\n",
"vi= 0.0009992 ##m^3\n",
"T= 60. ##C\n",
"T1= 20. ##C\n",
"T2= 40. ##C\n",
"vi1= 0.0010042 ##m^3\n",
"vi2= 0.0009886 ##m^3\n",
"v= 0.000951 ##m^3\n",
"v1= 0.0009992 ##m^3\n",
"v2= 0.0009956 ##m^3\n",
"##CALCULATIONS\n",
"B= (vi1-vi2)/(vi*(T-T1))\n",
"Kt= (v1-v2)/(v*(T2-T1))\n",
"Et= 1/Kt\n",
"##RESULTS\n",
"print'%s %.2e %s'% ('volume exapansion coefficient=',B,'L/s')\n",
"print'%s %.3e %s'% ('isothermal compressibility=',Kt,'Mpa')\n",
"print'%s %.f %s'% ('isothermal modulus of elasticity=',Et,'Mpa')\n",
"\n",
"\n",
"##ANSWER FOR Et GIVEN IN THE TEXTBOOK IS WRONG\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"volume exapansion coefficient= 3.90e-04 L/s\n",
"isothermal compressibility= 1.893e-04 Mpa\n",
"isothermal modulus of elasticity= 5283 Mpa\n"
]
}
],
"prompt_number": 4
}
],
"metadata": {}
}
]
}
|
