Homework SourseA steam turbine has an inlet state of 10MPa and 600C The tur
A steam turbine has an inlet state of 10MPa and 600°C. The turbine exit pressure is 100kPa.
What is the work [kJ/kg] that it produces if it is operating isentropic?
If the turbine is not isentropic but has an isentropic efficiency of 85%, how much work [kJ/kg] is it producing?
What is the most likely source of the entropy generation for a turbine?
Solution
Entropy generation or disorderness in system is due to losses in steam turbine due to which complete energy of steam cannot be recovered in form of mechanical energy. Major losses are:
Admission losses
Leakage losses
Friction losses: Frictional resistance is offered during flow of steam through nozzles on moving and stationary blades.
Now, in above question H1 = enthalpy of state 1 = 3625.84KJ/Kg
H2 = enthalpy of state 2 = 2505.63 KJ/Kg
when operating isentropically then work done = H1 - H2 = 1120.21 KJ/Kg
when isentropic efficiency is 85% then workdone = 0.85* ( H1 - H2)
= .85*1120.21 = 952.17 KJ/Kg
![A steam turbine has an inlet state of 10MPa and 600°C. The turbine exit pressure is 100kPa. What is the work [kJ/kg] that it produces if it is operating isentro](/WebImages/31/a-steam-turbine-has-an-inlet-state-of-10mpa-and-600c-the-tur-1087787-1761572261-0.webp "A steam turbine has an inlet state of 10MPa and 600°C. The turbine exit pressure is 100kPa. What is the work [kJ/kg] that it produces if it is operating isentro")
