1. Superheated steam at a pressure of 40 bar and a temperature of 500°C is supplied to the turbine of a Rankine cycle. If the condenser pressure is 0.03 bar, find the thermal efficiency of the cycle. Neglect feed pump work.
2. If the isentropic efficiency of the steam turbine in Question 1 above is 0.82, find:
(a) the enthalpy of the steam discharged into the condenser and
(b) the thermal efficiency of the cycle.
3. A steam turbine operates with a condenser pressure of 0.04 bar and has a single open-type regenerative feed heater. How much steam, at a pressure of 2 bar and a dryness fraction of 0.98, must be bled from the turbine to produce 1 kg of saturated feedwater at 2 bar?
4. Steam at 30 bar and 500°C enters a pass-out turbine at a rate of 18000 kg h-1. The bulk of this steam is expanded isentropically to a condenser pressure of 0.03 bar, but 32% is bled from the turbine at a pressure of 3 bar for process heating. If the condensate from the process heater is directly pumped back to the boiler, find:
(a) the power output from the turbine
(b) the rate of process heating
(c) the efficiency of the plant.