# CHAPTER 4: THE STEAM ENGINE¶

## Example 4.1 Page 46¶

In [6]:
#initialisation of variable
from math import pi,sqrt,acos,asin,atan,cos,sin,tan
p=90#lb/in^2
x1=0.9#lb
p1=10#lb/in^2
x2=0.81#lb
s1=161.5#lb.in^2
s2=89.1#lb.in^2
L1=496.8#lb.in^2
L2=545.5#lb.in^2

#CALCULATIONS
bc=(s1-s2)+(x1*L1)#C.H.U/lb
da=x2*L2#C.H.U/lb
W=bc-da#C.H.U/lb
R=W/bc*100#percent

#RESULTS
print"the work done per",round(R,3),"%"

the work done per 14.949 %


## Example 4.2 Page 47¶

In [8]:
#initialisation of variable
from math import pi,sqrt,acos,asin,atan,cos,sin,tan
h=1600.0#i.h.p
h1=20000.0#lb
h2=230.0#lb/in^2
T1=293.3#Degree C
x=25.91#in
v=30.0#in
T2=201#Degree C
T=T1-T2#degree C
x2=0.845#lb
L2=566.51#lb
s1=724#lb
h3=1400#C.H.U/hr
x=33000#ft^3

#CALCULATIONS
H=671.48#C.H.U/lb
ea=x2*L2#C.H.U/lb
W=H-ea#C.H.U/lb
R=W/H*100#percent
S=h2*s1#C.H.U
I=((h*x*60)/(h3*h1*s1))*100#percent
R1=I/R*100#pecent

#RESULTS
print"The indicated thermal efficiency ratio is",round(R1,3),"%"

The indicated thermal efficiency ratio is 54.433 %


## Example 4.3 Page 49¶

In [9]:
#initialisation of variable
from math import pi,sqrt,acos,asin,atan,cos,sin,tan
h1=180#lb/in^2
h2=3#lb/in^2
r1=60#percent
r2=90#percent
p3=100#lb/in^2
p4=10#lb/in^2
v1=4.4#ft^3/lb
v2=2*v1#ft^3
p=44#lb/in^2
x2=0.95#ft^3
s1=165.9#lb
s2=89.1#lb
L1=493.4#lb
H=(s1-s2)+L1#C.H.U/lb
W=65.8#C.H.U/lb

#CALCULATIONS
R=W/H*100#percent

#RESULTS
print"The rankine efficiency of the engine is",round(R,3),"%"

The rankine efficiency of the engine is 11.54 %


## Example 4.10 Page 52¶

In [11]:
#initialisation of variable
from math import pi,sqrt,acos,asin,atan,cos,sin,tan
p=85.0#lb/in^2
h=210.0#i.p.m
h1=8.0#in
h2=2.5#in
h3=20.0#in
x=0.75#in
p1=100.0#ln/in^2
x1=33000.0#in
p2=15.0#lb/in^2
v2=pi/4*(h1/12)**2*(h3/12)#ft^3
A=144*(29.08*1.6931-8.724)#ft/lb
d=x*A#ft/lb
v3=0.5816#ft^3
P=d/(144*v3)#lb/in^2
P1=pi/4*64#in^2
r=25*pi/16#in^2

#CALCULATIONS
H=P*(h3/12)*P1*h/(x1)
I=(P*(h3/12)*(P1-r)*h)/(x1)#I.h.P
T=H+I#I.h.p

#RESULTS
print"the h.p diameter of the piston and piston rod is",round(T,3),"I.h.p"

the h.p diameter of the piston and piston rod is 52.982 I.h.p


## Example 4.14 Page 55¶

In [14]:
#initialisation of variable
from math import pi,sqrt,acos,asin,atan,cos,sin,tan
a=1.025#in^2
h=18.0#in
h1=24.0#in
x=8.2#percent
v=15.0#in
v2=6.9#ft^3
p=0.74#lb/in^2
p1=50.0#lb/in^2
p2=83.0#lb/in^2
P3=48.0#lb/in
P1=29.8#lb/in^2
P2=14.6#lb/in^2
h2=29.8#in
D=(pi/4)*(3.0/2.0)**2*2#ft^3
v1=23400.0#ft.lb
W=a*v1#ft.lb
V=0.082*D#ft^3
Q=1.530#ft^3

#CALCULATIONS
I=V+Q#ft^3
P=P3+P2#lb/in^2
V1=p*v2#ft^3
W1=I/V1#lb
S=p2+P2#l/in^2
H=659.06#C.H.U/lb
T=W/(H*W1*1400)*100#percent

#RESULTS
print"The thermal efficiency of the engine is",round(T,3),"%"

The thermal efficiency of the engine is 7.294 %


## Example 4.16 Page 57¶

In [16]:
#initialisation of variable
from math import pi,sqrt,acos,asin,atan,cos,sin,tan
v=4.6#ft^3
h=5.0#percent
p=60.0#lb/in^2
p1=0.8#ft^3
p2=19.0#lb/in^2
a=100.0#r.p.m
h1=5920.0#lb
W=h1/(2*a*p)#lb
V=(0.25*v)#ft^3
v1=21.07#ft^3
w=V/v1#lb
H=W+w#lb
v2=H*7.17#ft^3
P=w*v2#ft^3
P1=0.675*v#ft^3

#CALCULATIONS
DP=P1/v2#ft^2

#RESULTS
print"The assumptions do you make in working out the dryness of the steam is",round(DP,3),"ft^3"

The assumptions do you make in working out the dryness of the steam is 0.79 ft^3


## Example 4.17 Page 58¶

In [18]:
#initialisation of variable
from math import pi,sqrt,acos,asin,atan,cos,sin,tan
h=0.08#lb
p=60#lb/in^2
p1=0.50#lb/in^2
v=0.5#ft^3
v1=7.17#ft^3
V=h*v1#ft^3

#CALCULATIONS
W=p1/v1#lb
I=v/v1#lb
M=h-I#lb

#RESULTS
print"The dryness of the steam at this pressure and missing quantity is",round(M,6),"lb"

The dryness of the steam at this pressure and missing quantity is 0.010265 lb


## Example 4.19 Page 59¶

In [19]:
#initialisation of variable
from math import pi,sqrt,acos,asin,atan,cos,sin,tan
p1=120#lb/in^2
p2=15#lb/in^2

#CALCULATIONS
v=1.65#lb
D=sqrt(v)#lb

#RESULTS
print"The above pressure are by gauge is",round(D,3),"lb"

The above pressure are by gauge is 1.285 lb


## Example 4.21 Page 61¶

In [21]:
#initialisation of variable
from math import pi,sqrt,acos,asin,atan,cos,sin,tan
p=150.0#lb/in^2
x=198.0#r.p.m
x1=33000.0#lb
h=2700.0#lb
h1=1400.0#lb
h2=51600.0#lb
r=165.0#C.H.U/lb
s=60.0#lb
t=48.0#Degree C
t1=11.0#degree C
t2=36.0#Degree C
P1=(40*75*t2*x)/(12*x1)#lb
P2=(38*70*t2*x)/(12*x1)#lb
L1=(t1*300*t2*x)/(12*x1)#lb
L2=(12*295*t2*x)/(12*x1)#lb
T=P1*P2*L1*L2#lb
H=5294#C.H.U/min
T1=h/s#lb/min
H1=T1*663#lb/min
H2=(h2/s*(36-11)+(h/s)*(t))#C.H.U
H3=(h/60)*t#C.H.U

#CALCULATIONS
TE=H/H1-H3*100#percent
R=r/(663-t)*100#percent

#RESULTS
print"The rankine efficiency is",round(R,3),"%"

The rankine efficiency is 26.829 %


## Example 4.23 Page 64¶

In [22]:
#initialisation of variable
from math import pi,sqrt,acos,asin,atan,cos,sin,tan
p1=100#ln/in^2
p2=2.5#lb/in^2
p3=20#lb/in^2
d=0.75#lb
p=0.5#lb
r=16#in
p4=p1/r#lb/in^2
P5=50#lb/in^2
W1=13960#ft/lb
W2=19040#ft/lb
T=33000#ft/lb
v=4.43#ft^3
v1=v*d#ft^3
W3=T*v1#ft/lb
Hp=3416#ft/lb
Lp=3416#ft/lb

#CALCULATIONS
W=Lp*v1#ft lb

#RESULTS
print"The thermal efficiency of a compound steam and work done is",round(W,3),"ft lb"

The thermal efficiency of a compound steam and work done is 11349.66 ft lb