Chapter 10 : Gaseous Mixtures

Example 10.1 pg : 262

In [1]:
			
# Variables
m = 2. 
M = 28.
M2 = 32.
PN = 300. 			#psia
Pt = 400.			#psia
			
# Calculations
nN = m/M
PO = Pt-PN
nO = nN*PO/PN
mO = M2*nO
			
# Results
print "Mass of oxygen added  =  %.3f lbm"%(mO)

Mass of oxygen added  =  0.762 lbm

Example 10.2 pg : 262

In [2]:
			
# Variables
n = 0.0714
R = 1545.
T = 560. 			#R
P = 400. 			#psia
VN = n*R*T/(P*144)
VO = (0.0238)*R*T/(P*144)
V = VN+VO
			
# Results
print "Total volume  =  %.3f ft**3"%(V)

Total volume  =  1.430 ft**3

Example 10.3 pg : 265

In [3]:
			
# Variables
import math 
m1 = 5.
m2 = 2.
cp1 = 0.248
cp2 = 0.203
T11 = 300. 			#F
T12 = 100. 			#F
P = 10. 			#psia
Pi = 20. 			#psia
Pf = 15. 			#psia
			
# Calculations
T2 = (m1*cp1*T11 + m2*cp2*T12)/(m1*cp1+m2*cp2)
n1 = m1/28.
n2 = m2/44.
n = n1+n2
P1 = P*n1/n
P2 = P*n2/n
dS = m2*(cp2*math.log((T2+460)/(T12+460)) - 35.1/778 *math.log(P2/Pi)) +m2*(cp2*math.log((T2+460)/(T12+460)) - 55.2/778 *math.log(P1/Pf))
			
# Results
print "change in enthalpy  =  %.2f B/R"%(dS)

change in enthalpy  =  0.49 B/R

Example 10.4 pg : 268

In [4]:
			
# Variables
Pg = 2.8886 			#psia
P = 25.      			#psia
phi = 0.5
			
# Calculations
pv = phi*Pg
pa = P-pv
w = 0.622*pv/pa
x = (w)/(1+w)
			
# Results
print "Mass fraction of water vapor in the mixture  =  %.4f lbm vapor/ lvm mixture"%(x)

Mass fraction of water vapor in the mixture  =  0.0367 lbm vapor/ lvm mixture

Example 10.5 pg : 271

In [5]:
			
# Variables
pgw = 0.5069 			#psia
p = 14.696   			#psia
Td = 100. 	    		#F
Tw = 80.     			#F
			
# Calculations
pv =  pgw- (p-pgw)*(Td-Tw)/(2800-Tw)
pg = 0.9492 			#psia
phi = pv/pg
			
# Results
print "relative humidity of air stream  =  %.1f percent"%(phi*100)

relative humidity of air stream  =  42.4 percent

Example 10.6 pg : 279

In [6]:
			
# Variables
w1 = 0.0176 			#lbm
w2 = 0.0093 			#lbm
T2d = 73.   			#F
T2 = 55.     			#F
			
# Calculations
hv1 = 1061+0.445*100
hv2 = 1061+0.445*55
hf = 23.06
q1 = 20.
q2 = 4.88
			
# Results
print "Heat removed in cooling section  =  %d Btu/lbm "%(q1)
print "Heat added in heating section  =  %.2f Btu/lbm "%(q2)

Heat removed in cooling section  =  20 Btu/lbm 
Heat added in heating section  =  4.88 Btu/lbm

Example 10.7 pg : 280

In [7]:
			
# Variables
Tdb = 115. 			#F
ph = 0.05

Twb = 67. 			#F
			
# Results
print ("From steam tables, Twb = 67 F")

From steam tables, Twb = 67 F

Example 10.8 pg : 280

In [8]:
			
# Variables
w1 = 206.
w2 = 55.
ma1 = 2.
ma2 = 3.
			
# Calculations
w3 =  (ma1*w1 + ma2*w2)/(ma1+ma2)
Tdb3 = 82.   			#F
TWb3 = 74.55 			#F
phi3 = 70. 	    		#percent
			
# Results
print "relative humidity  =  %d percent"%(phi3)
print " Dry bulb temperature  =  %d F"%(Tdb3)
print " Wet bulb temperature  =  %.2f F"%(TWb3)

relative humidity  =  70 percent
 Dry bulb temperature  =  82 F
 Wet bulb temperature  =  74.55 F