import math
# Variables
m = 1.5 #kg #mass of wet steam
mf = 0.08*m #kg #mass of liquid in wet steam
# Calculations and Results
x = (m-mf)/m #dryness fraction of mixture
print "Dryness fraction of mixture = %.2f"%(x)
import math
# Variables
x = 0.85 #quality of steam
print "The ratio of mass of saturated liquid to saturated steam = %.5f"%((1-x)/x)
import math
# Variables
p1 = 200. #kPa #initial pressure
t1 = 100. #°C #initial temperature
ts = 120.23 #°C #saturated steam temperature
# Calculations and Results
#From steam table
v1 = 0.001044 #m**3/kg #volume per kilogram of water
h1 = 419 #kJ/kg #enthalpy per kilogram of water
s1 = 1.3068 #kJ/kg #entropy per kilogram of water
u1 = h1-p1*v1 #kJ/kg #internal energy per kilogram of water
print "Volume per kilogram of water = %.6f m**3/kg"%(v1)
print "Enthalpy per kilogram of water = %.1f kJ/kg"%(h1)
print "Entropy per kilogram of water = %.4f kJ/kgK"%(s1)
print "Internal energy per kilogram of water = %.1f kJ/kg"%(u1)
import math
# Variables
p1 = 500. #kPa #initial pressure
s1 = 1.3625 #initial entropy
# Calculations and Results
#Using Method 2:
Ts = 424.28 #K #temperature at 500kPa
sf = 1.8606 #kJ/kgK #entropy at 500kPa
Cwat = 4.189 #kJ/kgK #specific heat of water
T1 = round((math.exp((sf-s1)/Cwat)/Ts)**-1) #K
print "Temperature = %.2f °C"%(T1-273)
v1 = 0.001 #m**3/kg #volume per kg water
h1 = (640.21 - Cwat*(151.86-T1+273)) # kJ/kg #Enthalpy per kg water
u1 = h1 - p1*v1 #kJ/kg #internal energy per kg water
print "Volume per kg water = %f m**3/kg"%(v1)
print "Enthalpy per kg water = %.1f kJ/kg"%(h1)
print "Internal energy per kg water = %.1f kJ/kg"%(u1)
# note : rounding off error. please check.
# Variables
t = 50. #°C #temperature of water
h = 209.31 #kJ/kg
# Calculations and Results
#From saturated property table
p = 12.35 #kPa
v = 0.001012 #m**3/kg
u = h - p*v #kJ/kg
s = 0.7037 #kJ/kg
print "Pressure = %.2f kPa"%(p)
print "Volume per kg water = %.6f m**3/kg"%(v)
print "Internal energy per kg water = %.1f kJ/kg"%(u)
print "Entropy per kg water = %.4f kJ/kgK"%(s)
# Variables
p = 12. #bar #pressure of steam leaving boiler
h = 2705. #kJ/kg #Enthalpy of steam
# Calculations and Results
#From pressure based saturated property table, at p = 12bar
hf = 798.64 #kJ/kg
hg = 2784.8 #kJ/kg
x = (h-hf)/(hg-hf) #Dryness fraction
v = (1-x)*0.001139 + (x)*0.1633 #m**3/kg
s = (1-x)*2.2165 + (x)*6.5233 #m**3/kgK
u = h - p*v*100 #kJ/kg
print "Volume per kg water = %.4f m**3/kg"%(v)
print "Internal energy per kg water = %.0f kJ/kg"%(u)
print "Entropy per kg water = %.3f kJ/kgK"%(s)
# Variables
p = 15 #bar
u = 2594.5 #kJ/kg
# Calculations and Results
#From saturated steam table based on pressure at p = 15 bar
hf = 844.87 #kJ/kg
hg = 2792.1 #kJ/kg
vf = 0.001154 #m**3/kg
vg = 0.13177 #m**3/kg
uf = hf-100*p*vf #kJ/kg
ug = hg-100*p*vg #kJ/kg
if u-ug<0.1 :
print "Temperature = %.2f °C"%(198.32)
print "Volume per kg water = %.5f m**3/kg"%(vg)
print "Enthalpy per kg water = %.1f kJ/kg"%(hg)
print "Internal energy per kg water = %.1f kJ/kg"%(ug)
print "Entropy per kg water = %.4f kJ/kgK"%(6.4448)
# Variables
p = 10e6 #Pa
t = 550. #°C
# Calculations and Results
#From superheated property table
v_500 = 0.03279 #m**3/kg
v_600 = 0.03837 #m**3/kg
v_550 = v_500 + (v_500-v_600)/(500-600)*(550-500) #m**3/kg
h_500 = 3373.6 #kJ/kg
h_600 = 3625.3 #kJ/kg
h_550 = h_500 + (h_500-h_600)/(500-600)*(550-500) #kJ/kg
s_500 = 6.5965 #kJ/kgK
s_600 = 6.9028 #kJ/kgK
s_550 = s_500 + (s_500-s_600)/(500-600)*(550-500) #kJ/kgK
print "Volume per kg water = %.6f m**3/kg"%(v_550)
print "Enthalpy per kg water = %.1f kJ/kg"%(h_550)
print "Entropy per kg water = %.4f kJ/kgK"%(s_550)
# Variables
t = 250. #°C
h = 2855.8 #kJ/kg
#From superheated property table
p = 3e6 #Pa
v = 0.07058 #m**3/kg
s = 6.2871 #kJ/kgK
u = h - p*v*.001 #kJ/kg
print "Pressure = %.1f MPa"%(p*1e-6)
print "Volume per kilogram of water = %.5f m**3/kg"%(v)
print "Enthalpy per kilogram of water = %.1f kJ/kg"%(h)
print "Entropy per kilogram of water = %.4f kJ/kgK"%(s)
print "Internal energy per kilogram of water = %.0f kJ/kg"%(u)
# variables
p = 2. #bar
m = 0.16 #kg
V = 0.1 #m**3
# Calculations and Results
#refereing to the saturation temperature corresponding to 2bar
v = V/m #m**3/kg
vf = 0.001061 #m**3/kg
vg = 0.8857 #m**3/kg
print 'Specific volume at saturated liquid phase vf) = %.6f m**3/kg '%(vf)
print 'Specific volume at saturated vapor phase vg) = %.6f m**3/kg '%(vg)
if v<vg and v>vf :
print 'The temperature of the steam must be equal to saturation temperature corresponding to 2 bar'
print "Temperature of steam = %.2f °C"%(120.23)
# Variables
p1 = 2. #bar
v1 = 0.624 #m**3/kg
t = 120.23 #°C
m = 0.16 #kg
# Calculations and Results
vf = 0.001061 #m**3/kg
vg = 0.8857 #m**3/kg
x1 = (v1-vf)/(vg-vf) #Dryness fraction
hf = 504.68 #kJ/kg
hg = 2706.6 #kJ/kg
h1 = (1-x1)*hf + x1*hg #kJ/kg
u1 = h1 - p1*v1*100 #kJ/kg
v2 = v1 #m**3/kg
vf = 0.001044 #m**3/kg
vg = 1.673 #m**3/kg
x2 = (v1-vf)/(vg-vf) #Dryness fraction
hf = 419. #kJ/kg
hg = 2676. #kJ/kg
h2 = (1-x2)*hf + x2*hg #kJ/kg
p2 = 1.010325 #bar
u2 = h2 - (p2*100)*v2 #kJ/kg
print "Heat rejected from steam = %.1f kJ"%(m*(u2-u1))
# Variables
m =0.1 #kg
p1 = 10. #bar
p2 = 1. #bar
# Calculations and Results
#From saturated steam table
v1 = 0.1944 #m**3/kg
v2 = (p1/p2)**(1/1.3)*v1 #m**3/kg
W = m*(p1*v1-p2*v2)*100/(1.3-1) #kJ
print "Work during expansion process = %.2f kJ"%(W)
h1 = 2778.1 #kJ/kg
u1 = (h1 - p1*v1*100) #kJ/kg
vf = 0.001043 #m**3/kg
vg = 1.694 #m**3/kg
x2 = (v2-vf)/(vg-vf) #Dryness fraction
hf = 417.33 #kJ/kg
hg = 2675.5 #kJ/kg
h2 = (1-x2)*hf + x2*hg #kJ/kg
u2 = h2 - p2*v2*100 #kJ/kg
print "Heat rejected from steam = %.2f kJ"%(W+m*(u2-u1))
# note : rounding off error
# Variables
p1 = 10. #bar
t1 = 300. #°C
V1 = 50. #m/s
p2 = 1. #bar
m = 1.2 #kg/s
# Calculations and Results
#From superheated steam table
h1 = 3051.2 #kJ/kg
s1 = 7.1228 #kJ/kgK
p2 = 1 #bar
s2 = s1 #kJ/kgK
sf = 1.3025 #kJ/kgK
sg = 7.3593 #kJ/kgK
x2 = (s2-sf)/(sg-sf) #Dryness fraction
hf = 417.44 #kJ/kg
hg = 2675.5 #kJ/kg
h2 = (1-x2)*hf + x2*hg #kJ/kg
vf = 0.001043 #m**3/kg
vg = 1.694 #m**3/kg
v2 = (1-x2)*vf + x2*vg #m**3/kg
V2 = (2*(1000*(h1-h2))+V1**2)**0.5 #m/s
A2 = m*v2/V2*10000 #cm**3
print "The exit area of the nozzle = %.1f cm**2"%(A2)
# Variables
m1 = 0.2 #kg/s
p = 4. #bar
# Calculations and Results
#From superheated steam table
h1 = 2752.8 #kJ/kg
h2 = 209.31 #kJ/kg
h3 = 604.73 #kJ/kg
m2 = (m1*h1-m1*h3)/(h3-h2) #kg/s
print "The flow rate of feed water into the heater = %.3f kg/s"%(m2)