Question

- Question 3 Superheated steam at a pressure and temperature of 60 bar and 450 degC undergoes adiabatic expansion through a turbine at a steady rate of 16.3 kg/s. The steam exits the turbine in a wet condition with a pressure of 0.34 bar and specific enthalpy of 2,355 kJ/kg. 25 points Determine the How Did I Do?

Answer 1

at exit of turbine at 0.34 bar

hf=301.5 KJ/kg and hfg=2328.9 KJ/kg

now enthalpy at this state=2355 KJ/kg

so 2355=301.5+x(2328.9)

x is quality of steam

x=0.8817 or 88.17 %

now entropy at this state =sf+xsfg= 0.980+6.747*0.88=6.91736 KJ/KgK ans

specific volume =vf+x(vg-vf) = 0.001024+0.88(4.650-0.001024) =4.0921 m3/kg

internal energy = uf+xufg = 580+0.88*(1966) =2310.08 KJ/Kg Ans(there may be some variation as u at 0.34 bar not available so approximated data at 0.35 bar was used)

3.

Power output=mass flow rate*(h1-h2) =16.3*(3301-2355) =15403.5 KW or 15.4035 MW Ans