# Chapter 13 : Hydraulic Power Transmission|¶

## Example 13.1 Page No : 512¶

In [4]:
import math

#initialisation of variables
nop= 0.88
nom= 0.88   # constant
Pm= 75.  	#hp
p= 3000. 	#lb/in**2 pressure
d= 54.5 	#lbm/ft**3 density
u= 1.05*10**-4  # viscosity
d1= 0.5 	#in
g= 32.2 	#ft/sec**2

#CALCULATIONS
nt= (7./11)*nop*nom
pp= Pm/nt
Q= nop*pp*550/(p*144)
Re= 4*d*Q/(math.pi*u*(d1/12)*g)

#RESULTS
print  ' ntrans = %.3f '%(nt)
print  ' Input power = %.f hp'%(pp)
print  ' Flow rate = %.3f ft**3/sec'%(Q)
print  ' Reynolds Number = %.1e '%(Re)

 ntrans = 0.493
Input power = 152 hp
Flow rate = 0.171 ft**3/sec
Reynolds Number = 8.4e+04


## Example 13.2 Page No : 513¶

In [5]:
import math

#initialisation of variables
lc= 0.25
a= 90.   	#degrees
p= 3000.     	#lb/in**2 pressure
g= 32.2 	#ft/sec**2
d1= 0.5 	#in
Q= 0.171 	#ft**3/sec
d= 54.5 	#lbm/ft**3 density
n1= 2.
n2= 6.
lc1= 0.9
nop= 0.88
nom= 0.88

#CALCULATIONS
P1= 4*p*144/11
P2= 8*d*Q**2*(n1*lc+n2*lc1)/(math.pi**2*(d1/12)**4*g)
pt= P1+P2
dpm= (p*144-pt)
ntrans= nop*nom*dpm/(p*144)

#RESULTS
print  ' Frictional pressure drop = %.2e lbf/ft**2'%(P1)
print  ' Extra Frictional pressure drop = %.2e lbf/ft**2'%(P2)
print  ' Total pressure drop = %.2e lbf/ft**2'%(pt)
print  ' Motor pressure drop = %.2e lbf/ft**2'%(dpm)
print  ' Overall transmission coefficiency = %.3f'%(ntrans)

 Frictional pressure drop = 1.57e+05 lbf/ft**2
Extra Frictional pressure drop = 7.85e+04 lbf/ft**2
Total pressure drop = 2.36e+05 lbf/ft**2
Motor pressure drop = 1.96e+05 lbf/ft**2
Overall transmission coefficiency = 0.352


## Example 13.3 Page No : 521¶

In [6]:
import math

#initialisation of variables
bip= 135. 	#degrees inlet angle
bop= 150. 	#degrees outlet angle
bot= 140. 	#degrees turbine outlet angle
bos= 137. 	#degrees stator blade outlet angle
r= 1.8
r1= 1.8    # ratio b1/b2
r2= 0.7    # ratio b1/b3
r3= 0.95   # ratio r3/r1

#CALCULATIONS

 R1 = 3.37