question archive In normal situations, a 75 kW steam power plant (shown in the figure below) is operated with the expansion valve closed
In normal situations, a 75 kW steam power plant (shown in the figure below) is operated with the expansion valve closed
Subject:Mechanical EngineeringPrice: Bought3
In normal situations, a 75 kW steam power plant (shown in the figure below) is operated with the expansion valve closed. The boiler (not shown here) passes through the high-pressure turbine to the superheater (shown as reheat boiler) and into the low-pressure turbine. When the high-pressure turbine is out of service, the plant is operated in an emergency mode such that the steam from the boiler is passed through the expansion valve directly into the low-pressure turbine.
Data: p1 = 5 kPa; p2 = 10 MPa; p5 = 0.5 MPa; x1 = 0; T3 = 500 °C; T5 = 480 °C. Isentropic efficiency of both the turbines are 90% and the pump may be assumed to be operating isentropically.
(a) Draw the two cycles (ordinary and emergency) on a T-s diagram
(b) Calculate the efficiency of each cycle
(c) Calculate the mass flow rate of the steam in the ordinary operating mode
(d) Calculate the output power in the emergency cycle for the same mass flow rate.
