{
"metadata": {
"name": "",
"signature": "sha256:3303c10fbdf0badf34a5e53239631d65156a6198f60e9dc97e75e274501b7ad0"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 1 : Introduction"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 1.1 Page No : 3"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math \n",
"\n",
"#Given:\n",
"n = 4. #Number of cylinders\n",
"d = 68./10 #Bore in cm\n",
"l = 75./10 #Stroke in cm\n",
"r = 8. #Compression ratio\n",
"\n",
"#Solution:\n",
"V_s = (math.pi/4)*d**2*l #Swept volume of one cylinder in cm**3\n",
"cubic_capacity = n*V_s #Cubic capacity in cm**3\n",
"#Since, r = (V_c + V_s)/V_c\n",
"V_c = V_s/(r-1) #Clearance volume in cm**3\n",
"\n",
"#Results:\n",
"print \" The cubic capacity of the engine = %.1f cm**3\"%(cubic_capacity)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" The cubic capacity of the engine = 1089.5 cm**3\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 1.2 Page No : 8"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"\n",
"#Given:\n",
"ip = 10. #Indicated power in kW\n",
"eta_m = 80. #Mechanical efficiency in percent\n",
"\n",
"#Solution:\n",
"#Since, eta_m = bp/ip\n",
"bp = (eta_m/100)*ip #Brake power in kW\n",
"fp = ip-bp #Friction power in kW\n",
"\n",
"#Results:\n",
"print \" The brake power delivered, bp = %d kW\"%(bp)\n",
"print \" The friction power, fp = %d kW\"%(fp)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" The brake power delivered, bp = 8 kW\n",
" The friction power, fp = 2 kW\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 1.3 Page No : 13"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math \n",
"\n",
"#Given:\n",
"bp = 100. #Brake power at full load in kW\n",
"fp = 25. #Frictional power in kW (printing error)\n",
"\n",
"#Solution:\n",
"eta_m = bp/(bp+fp) #Mechanical efficiency at full load\n",
"#(a)At half load\n",
"bp = bp/2 #Brake power at half load in kW\n",
"eta_m1 = bp/(bp+fp) #Mechanical efficiency at half load\n",
"#(b)At quarter load\n",
"bp = bp/2 #Brake power at quarter load in kW\n",
"eta_m2 = bp/(bp+fp) #Mechanical efficiency at quarter load\n",
"\n",
"#Results:\n",
"print \" The mechanical efficiency at full load, eta_m = %d percent\"%(eta_m*100)\n",
"print \" The mechanical efficiency, \\\n",
"\\na)At half load, eta_m = %.1f percent \\\n",
"\\nb)At quarter load, eta_m = %d percent\"%(eta_m1*100,eta_m2*100)\n",
"\n",
"#Data in the book is printed wrong\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" The mechanical efficiency at full load, eta_m = 80 percent\n",
" The mechanical efficiency, \n",
"a)At half load, eta_m = 66.7 percent \n",
"b)At quarter load, eta_m = 50 percent\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 1.4 Page No : 18"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math \n",
"#Calculations on four stroke petrol engine\n",
"#Given:\n",
"bp = 35. #Brake power in kW\n",
"eta_m = 80. #Mechanical efficiency in percent\n",
"bsfc = 0.4 #Brake specific fuel consumption in kg/kWh\n",
"A_F = 14./1 #Air-fuel ratio\n",
"CV = 43000. #Calorific value in kJ/kg\n",
"\n",
"#Solution:\n",
"#(a)\n",
"ip = bp*100/eta_m #Indicated power in kW\n",
"#(b)\n",
"fp = ip-bp #Frictional power in kW\n",
"#(c)\n",
"#Since, 1 kWh = 3600 kJ\n",
"eta_bt = 1/(bsfc*CV/3600) #Brake thermal efficiency\n",
"#(d)\n",
"eta_it = eta_bt/eta_m*100 #Indicated thermal efficiency\n",
"#(e)\n",
"m_f = bsfc*bp #Fuel consumption in kg/hr\n",
"#(f)\n",
"m_a = A_F*m_f #Air consumption in kg/hr\n",
"\n",
"\n",
"#Results:\n",
"print \" a)The indicated power, ip = %.2f kW \\\n",
"\\nb)The friction power, fp = %.2f kW\"%(ip,fp)\n",
"print \" c)The brake thermal efficiency, eta_bt = %.1f percent \\\n",
"\\nd)The indicated thermal efficiency, eta_it = %.1f percent\"%(eta_bt*100,eta_it*100)\n",
"print \" e)The fuel consumption per hour, m_f = %.1f kg/hr \\\n",
"\\nf)The air consumption per hour, m_a = %d kg/hr\"%(m_f,m_a)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" a)The indicated power, ip = 43.75 kW \n",
"b)The friction power, fp = 8.75 kW\n",
" c)The brake thermal efficiency, eta_bt = 20.9 percent \n",
"d)The indicated thermal efficiency, eta_it = 26.2 percent\n",
" e)The fuel consumption per hour, m_f = 14.0 kg/hr \n",
"f)The air consumption per hour, m_a = 196 kg/hr\n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 1.5 Page No : 23"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Given:\n",
"F_A = 0.07/1 #Fuel-air ratio\n",
"bp = 75. #Brake power in kW\n",
"eta_bt = 20. #Brake thermal efficiency in percent\n",
"rho_a = 1.2 #Density of air in kg/m**3\n",
"rho_f = 4*rho_a #Density of fuel vapour in kg/m**3\n",
"CV = 43700. #Calorific value of fuel in kJ/kg\n",
" \n",
"#Solution:\n",
"m_f = bp*3600/(eta_bt*CV/100) #Fuel consumption in kg/hr\n",
"m_a = m_f/F_A #Air consumption in kg/hr\n",
"V_a = m_a/rho_a #Volume of air in m**3/hr\n",
"V_f = m_f/rho_f #Volume of fuel in m**3/hr\n",
"V_mixture = V_f+V_a #Mixture volume in m**3/hr\n",
" \n",
"#Results:\n",
"print \" The air consumption, m_a = %.1f kg/hr\"%(m_a)\n",
"print \" The volume of air required, V_a = %.1f m**3/hr\"%(V_a)\n",
"print \" The volume of mixture required = %.1f m**3/hr\"%(V_mixture) #printing error)\n",
" #Answer in the book is printed wrong\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" The air consumption, m_a = 441.3 kg/hr\n",
" The volume of air required, V_a = 367.8 m**3/hr\n",
" The volume of mixture required = 374.2 m**3/hr\n"
]
}
],
"prompt_number": 7
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 1.6 Page No : 28"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"#Given:\n",
"bp = 5. #Brake power in kW\n",
"eta_it = 30. #Indicated thermal efficiency in percent\n",
"eta_m = 75. #Mechanical efficiency in percent (printing error)\n",
"\n",
"#Solution:\n",
"ip = bp*100/eta_m #Indicated power in kW\n",
"CV = 42000. #Calorific value of diesel(fuel) in kJ/kg\n",
"m_f = ip*3600/(eta_it*CV/100) #Fuel consumption in kg/hr\n",
"#Density of diesel(fuel) = 0.87 kg/l\n",
"rho_f = 0.87 #Density of fuel in kg/l\n",
"V_f = m_f/rho_f #Fuel consumption in l/hr\n",
"isfc = m_f/ip #Indicated specific fuel consumption in kg/kWh\n",
"bsfc = m_f/bp #Brake specific fuel consumption in kg/kWh\n",
"\n",
"#Results:\n",
"print \" The fuel consumption of engine, m_f in, \\\n",
"\\na)kg/hr = %.3f kg/hr \\\n",
"\\nb)litres/hr = %.2f l/hr\"%(m_f,V_f)\n",
"print \" c)Indicated specific fuel consumption, isfc = %.3f kg/kWh\"%(isfc)\n",
"print \" d)Brake specific fuel consumption, bsfc = %.3f kg/kWh\"%(bsfc)\n",
"#Data in the book is printed wrong\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" The fuel consumption of engine, m_f in, \n",
"a)kg/hr = 1.905 kg/hr \n",
"b)litres/hr = 2.19 l/hr\n",
" c)Indicated specific fuel consumption, isfc = 0.286 kg/kWh\n",
" d)Brake specific fuel consumption, bsfc = 0.381 kg/kWh\n"
]
}
],
"prompt_number": 9
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 1.7 Page No : 33"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"#Given:\n",
"bp = 5000. #Brake power in kW\n",
"fp = 1000. #Friction power in kW\n",
"m_f = 2300. #Fuel consumption in kg/hr\n",
"A_F = 20./1 #Air-fuel ratio\n",
"CV = 42000. #Calorific value of fuel in kJ/kg\n",
"\n",
"#Solution:\n",
"#(a)\n",
"ip = bp+fp #Indicated power in kW\n",
"#(b)\n",
"eta_m = bp/ip #Mechanical efficiency\n",
"#(c)\n",
"m_a = A_F*m_f #Air consumption in kg/hr\n",
"#(d)\n",
"eta_it = ip*3600/(m_f*CV) #Indicated thermal efficiency\n",
"#(e)\n",
"eta_bt = eta_it*eta_m #Brake thermal efficiency\n",
"\n",
"#Results:\n",
"print \" a)The indicated power, ip = %d kW\"%(ip)\n",
"print \" b)The mechanical efficiency, eta_m = %d percent\"%(eta_m*100)\n",
"print \" c)The air consumption, m_a = %d kg/hr\"%(m_a)\n",
"print \" d)The indicated thermal efficiency, eta_it = %.1f percent \\\n",
"\\ne)The brake thermal efficiency, eta_bt = %.1f percent\"%(eta_it*100,eta_bt*100)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" a)The indicated power, ip = 6000 kW\n",
" b)The mechanical efficiency, eta_m = 83 percent\n",
" c)The air consumption, m_a = 46000 kg/hr\n",
" d)The indicated thermal efficiency, eta_it = 22.4 percent \n",
"e)The brake thermal efficiency, eta_bt = 18.6 percent\n"
]
}
],
"prompt_number": 11
}
],
"metadata": {}
}
]
}