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{
"metadata": {
"name": "",
"signature": "sha256:796b0d55d49c3a8708377f5eda9102cc03f40afdc4e2bd80f2e4fc59de97aea2"
},
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"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 4 : The First Law of Thermodynamics for Systems-Pure Substances"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.1 Page No : 93"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\t\t\t\n",
"# Variables\n",
"#four heat transfer\n",
"Q_1 = 900 \t\t\t#J\n",
"Q_2 = 80 \t\t\t#J\n",
"Q_3 = -800 \t\t\t#J\n",
"Q_4 = 150 \t\t\t#J\n",
"#four work interactions\n",
"W_1 = 200 \t\t\t#J\n",
"W_2 = 150 \t\t\t#J\n",
"W_3 = 300 \t\t\t#J\n",
"\t\t\t#W_4\n",
"\t\t\t\n",
"# Calculations and Results\n",
"W_4 = Q_1 +Q_2 +Q_3 +Q_4 -W_1 -W_2 -W_3 \n",
"print \"Magnitude and Direction of the fourth work interaction, W4 = %.0f J\"%(W_4)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Magnitude and Direction of the fourth work interaction, W4 = -320 J\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.2 Page No : 94"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\t\t\t\n",
"# Variables\n",
"Q_a = -50 \t\t\t#KJ \t\t\t#heat transferred from the system along path A\n",
"W_a = -65 \t\t\t#KJ \t\t\t#work done along path A\n",
"Q_b = 0 \t\t\t#KJ \t\t\t#heat transferred from the system along path B\n",
"\t\t\t#W_b work done along path B\n",
"\n",
"\t\t\t\n",
"# Calculations and Results\n",
"\n",
"#Part(a)\n",
"print \"Part a\";\n",
"delE_a = Q_a - W_a \t\t\t#KJ \t\t\t#Change in energy along path A\n",
"print \"Change in energy of the system = %.0f KJ\"%(delE_a);\n",
"\n",
"#Part(b)\n",
"print \"Part b\";\n",
"delE_b = -1*delE_a \t\t\t#KJ \t\t\t#Change in energy along path B\n",
"W_b = delE_b - Q_b \t\t\t#KJ \t\t\t#work done along path B\n",
"print \"Magnitude and direction of work done during B, W_b = %.0f KJ\"%(W_b)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Part a\n",
"Change in energy of the system = 15 KJ\n",
"Part b\n",
"Magnitude and direction of work done during B, W_b = -15 KJ\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.3 Page No : 99"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"# Variables\n",
"m = 2.3 \t\t\t#kg \t\t\t#mass of substance\n",
"u = 21 * 10**3 \t\t\t#J/kg \t\t\t#internal energy\n",
"V = 110. \t\t\t#m/s \t\t\t#velocity \n",
"z = 1500. \t\t\t#m \t\t\t#elevation above sea level\n",
"g = 9.81 \t\t\t#m/s**2 \t\t\t#acceleration due to gravity\n",
"\n",
"\n",
"\t\t\t\n",
"# Calculations and Results\n",
"E = m*(g*z + V**2/2 + u) \t\t\t#J/kg \t\t\t#Total energy of the system\n",
"print \"The total energy of the system with respect to an observer at rest at sea level, E = %.4f KJ\"%(0.001*E);\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The total energy of the system with respect to an observer at rest at sea level, E = 96.0595 KJ\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4.4 Page No : 103"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from numpy import *\n",
"from sympy import Derivative\n",
"\t\t\t\n",
"# Variables\n",
"t = poly1d(0); \t\t\t#C \t\t\t#Temperature in C\n",
"u = 196. + .718*t; \t\t\t#KJ/kg \t\t\t#specific internal energy\n",
"pv = 287*(t+273.); \t\t\t#Nm/kg \t\t\t#p is pressure and v = specific volume\n",
"\n",
"\t\t\t\n",
"# Calculations and Results\n",
"Cv = poly(u);\n",
"print \"Specific heat at constant volume,Cv = %.3f kJ/kgK\"%(Cv[0])\n",
"\n",
"h = u + pv*.001 \t\t\t#KJ/kg \t\t\t#enthalpy\n",
"Cp = poly(h);\n",
"print \"Specific heat at constant pressure,Cp = %.3f kJ/kgK\"%(Cp[0])\n",
"\n",
"# Note: Poly function gives different result then book has."
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Specific heat at constant volume,Cv = 1.000 kJ/kgK\n",
"Specific heat at constant pressure,Cp = 1.000 kJ/kgK\n"
]
}
],
"prompt_number": 6
}
],
"metadata": {}
}
]
}
|
