One technique for operating a steam turbine in part-load power output is to throttle the steam to a lower pressure before it enters the turbine, as shown in Fig. P9.39. The streamline conditions are 2 MPa, 400°C, and the turbine exhaust pressure is fixed at 10 kPa. Assuming the expansion inside the turbine to be reversible and adiabatic, determine
a. The full-load specific work output of the turbine
b. The pressure the steam must be throttled to for 80% of full-load output
c. Show both processes in a T–s diagram.