Chapter 1 : Introduction

Example 1.1 Page no : 7

In [1]:
					
#Input data
BHP = 51.					#Brake horse power in h.p
N = 1000.					#Speed in r.p.m
FHP = 17.					#Friction horse power in h.p

					
#Calculations
IHP = (BHP+FHP)					#Indicated Horse power in h.p
mn = (BHP/IHP)*100					#Mechanical efficiency in percent

					
#Output
print 'Mechanical efficiency of the engine is %i percent'%(mn)

Mechanical efficiency of the engine is 75 percent

Example 1.2 Page no : 10

In [2]:
#Data taken from Ex.No.1
BHP = 51.					#Brake horse power in h.p
N = 1000.					#Speed in r.p.m
FHP = 17.					#Friction horse power in h.p
					
#Input data
O1 = BHP/2					#Half of b.h.p output in h.p
O2 = 10					#Brake horse power in h.p

					
#Calculations
#Case(i)
IHP1 = (O1+FHP)					#Indicated Horse power in h.p
mn1 = (O1/IHP1)*100					#Mechanical efficiency in percent

#Case(ii)
IHP2 = (O2+FHP)					#Indicated Horse power in h.p
mn2 = (O2/IHP2)*100					#Mechanical efficiency in percent


					
#Output
print 'Mechanical efficiency of the engine when it delivers  \
\na) Half the b.h.p output is %3.0f percent  \
\nb) 10 b.h.p is %3.0f percent'%(mn1,mn2)

Mechanical efficiency of the engine when it delivers  
a) Half the b.h.p output is  60 percent  
b) 10 b.h.p is  37 percent

Example 1.3 Page no : 12

In [3]:
import math 
					
#Input data
Fc = 220.					#Fuel consumption in gm/(b.h.p*hr)
CV = 10600.					#Calorific value in kcal/kg

					
#Calculations
hf = (Fc/1000)*CV					#Heat supplied in kcal/hr
O = 632.					
#Output in terms of kcal/hr
bn = (O/hf)*100					#Brake thermal efficiency in percent

					
#Output
print 'Brake thermal efficiency is %3.1f percent'%(bn)

Brake thermal efficiency is 27.1 percent

Example 1.4 Page no : 12

In [4]:
import math 
					
#Input data
IHP = 45.					#Indicated horse power in h.p
Fc = 13.					#Fuel consumption in litres/hr
g = 0.8					#Specific gravity of oil
nm = 80.					#Mechanical efficiency in percent
CV = 10000.					#Calorific value of fuel in kcal/kg

					
#Calculations
BHP = (IHP*nm)/100					#Brake horse power in h.p
hi = (Fc*g*CV)					#Heat supplied in kcal/hour
In = ((IHP*4500*60)/(427*hi))*100					#Indicated thermal efficiency in percent
Bn = (In*(nm/100))					#Brake thermal efficiency in percent

					
#Output
print 'Indicated thermal efficiency is %3.2f percent  \
\nBrake thermal efficiency is %3.2f percent'%(In,Bn)

Indicated thermal efficiency is 27.36 percent  
Brake thermal efficiency is 21.89 percent

Example 1.5 Page no : 13

In [5]:
import math 
					
#Input data
BHP = 15.					#Brake horse power in h.p
In = 28.					#Indicated thermal efficiency in percent
mn = 75.					#Mechanical efficiency in percent
CV = 10000.					#Calorific value of fuel in kcal/kg

					
#Calculations
Bn = ((In/100)*(mn/100))*100					#Brake thermal efficiency in percent
I = (BHP/(Bn/100))*((4500.*60)/427)					#Input in kcal/hr
Fc = (I/CV)					#Fuel consumption in kg/hr

					
#Output
print 'Fuel consumption of the engine is %3.2f kg/hr'%(Fc)

Fuel consumption of the engine is 4.52 kg/hr