Chapter 14 : Similarity Laws and Factors for Turbomachines

Example 14.1 Page No : 479

In [2]:
import math

#Initialization of variables
g = 9.81 	#kN/m**3
Q = 3.2 	#m**3/s
h = 25   	#m
eta = 0.82
	
#calculations
bp =  g*Q*h/eta
	
#Results
print "Brake power  =  %d kW"%(bp)

#Initialization of variables
D1 = 50.
n1 = 1450.
n2 = 1200.
D2 = 80.
Q1 = 3.2 	#cfs
h1 = 25. 	#m
g = 9.81 	#kN/m**3
eta = 0.82
	
#calculations
h2 = h1*(D2/D1)**2 *(n2/n1)**2
Q2 = Q1*(D2/D1)**3 *(n2/n1)
bp = g*Q2*h2/eta
h1 = 82. 	    #ft
Q1 = 50700. 	#gpm
h2 = 143.8 	#ft
Q2 = 171800 	#gpm
Ns1 = n1*math.sqrt(Q1) /h1**(3/4.) 
Ns2 = n2*math.sqrt(Q2) /h2**(3/4.) 
	
#Results
print "Brake power  =  %d kW"%(round(bp,-1))
print "Pumps are homologous. We expect them to have same specific speed and their speeds are %.1f and \
%.1f"%(round(Ns1,-1),round(Ns2,-1))
Brake power  =  957 kW
Brake power  =  5690 kW
Pumps are homologous. We expect them to have same specific speed and their speeds are 11980.0 and 11980.0