Chapter 5 : Control-Volume Analysis

Example 5.1 Page No : 114

In [1]:
	
#initialisation of variables
w= 20.   	#lbm/sec plant rate
sh= 0.004
mw2= 0.12 	#lbm/sec stream rate
ma3= 12.2 	#lbm/sec rates of air
mw3= 0.130 	#lbm/sec water rate
	
#CALCULATIONS
mw1= w/((1/sh)+1)
ma1= w-mw1
ma4= ma1-ma3
mw4= mw1+mw2-mw3
mr= ma4+mw4
sh1= mw4/ma4
	
#RESULTS
print  ' mw1 = %.4f lbm/sec'%(mw1)
print  ' ma1 = %.2f lbm/sec'%(ma1)
print  ' ma4 = %.2f lbm/sec'%(ma4)
print  ' mw4 = %.4f lbm/sec'%(mw4)
print  ' mr = %.2f lbm/sec'%(mr)
print  ' specific humidity = %.5f lbm/sec'%(sh1)

 mw1 = 0.0797 lbm/sec
 ma1 = 19.92 lbm/sec
 ma4 = 7.72 lbm/sec
 mw4 = 0.0697 lbm/sec
 mr = 7.79 lbm/sec
 specific humidity = 0.00903 lbm/sec

Example 5.2 Page No : 131

In [2]:
import math 
	
#initialisation of variables
w= 62.4 	#lbf/ft**3 fluid density
g= 32.2 	#ft/sec**2 
v= 86.5 	#ft/sec velocity
d2= 3.  	#in
d1= 6.  	#in
dp= 50. 	#lbf/in**2 gauge pressure
	
#CALCULATIONS
Fb= ((math.pi*(w/g)*v**2*(1/d1)**2*(1-(d2/d1)**2)*0.25)-dp*144*(math.pi/4)*(1/d2)**2)
	
#RESULTS
print  'Load on the bolts = %.f lbf'%(Fb)

Load on the bolts = -391 lbf

Example 5.3 Page No : 133

In [3]:
import math 
	
#initialisation of variables
F1= 237. 	#lb
dp= 50. 	#lbf/in**2
D= 6.    	#in diameter
	
#CALCULATIONS
F2= dp*144*(math.pi/4)*(D/12)**2
Fb= F1-F2
	
#RESULTS

print  'Load on the bolts = %.f lbf'%(Fb)
#rounding-off error

Load on the bolts = -1177 lbf

Example 5.5 Page No : 137

In [4]:
import math 
	
#initialisation of variables
w1= 0.0286 	#lbm/ft**3 density
v= 2500. 	#ft/sec velocity
A= 2.5   	#ft**3 area
k= 0.015
p2= 700. 	#lbf/ft**2
p1= 628. 	#lbf/ft**2 pressure
v2= 3500. 	#ft/sec outlet
g= 32.17 	#ft/sec**2
	
#CALCULATIONS
ma= w1*v*A
mf= round(k*ma,2)
mt= round(ma+mf,1)
F= (p2-p1)*A+(mt*v2/g)-(ma*v/g)


#RESULTS
print  ' air mass flow rate = %.2f lbm/sec'%(ma)
print  ' Fuel flow rate = %.2f lbm/sec'%(mf)
print  ' Fuel flow rate at station 2 = %.2f lbm/sec'%(mt)
print  ' Thrust force = %d lbf'%(round(F,-1))

 air mass flow rate = 178.75 lbm/sec
 Fuel flow rate = 2.68 lbm/sec
 Fuel flow rate at station 2 = 181.40 lbm/sec
 Thrust force = 6020 lbf