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