Steam expands in an adiabatic turbine from 8 MPa and 450°C to a pressure of 50 kPa at a rate of 1.8 kg/s. The maximum power output of the turbine is
A)1129 kW
B)995 kW
C)2136 kW
D)718 kW
E)1791 kW

Question

Quizplus · Accepted Answer

Solved by EES Software. Solutions can be verified by copying-and-pasting the following lines on a blank EES screen. 
P1=8000 "kPa"
T1=450 "C"
P2=50 "kPa"
m=1.8 "kg/s"
h1=ENTHALPY(Steam_IAPWS,T=T1,P=P1)
s1=ENTROPY(Steam_IAPWS,T=T1,P=P1)
h2=ENTHALPY(Steam_IAPWS, s=s1,P=P2)
W_out=m*(h1-h2) 
"Some Wrong Solutions with Common Mistakes:"
h22=ENTHALPY(Steam_IAPWS,x=1,P=P2) "Assuming sat. vapor at turbine exit"
W1_Wout=m*(h1-h22)
W2_Wout=h1-h2 "Not using mass flow rate"

Steam Expands in an Adiabatic Turbine from 8 MPa and 450°C