Q1. Given that the internal energy of water at 55 bar pressure is 1178 kJ kg-1 and that the specific volume of water at this pressure is 0.13 × 10-2 m3 kg-1, calculate the specific enthalpy of water at 55 bar pressure.
Q2.Superheated steam at a pressure of 40 bar and a temperature of500°C is supplied to the turbine of a Rankine cycle.
(a) If the condenser pressure is 0.03 bar, find the thermal efficiency of the cycle. Neglectfeed pump work.
(b) If the isentropic efficiency of the steam turbine in part (a) above is0.82, find:
(i) The enthalpy of the steam discharged into the condenser and
(ii) The thermal efficiency of the cycle.
Q3. Steam at 30 bar and 500°C enters a pass-out turbine at a rate of18000 kg h-1. The bulk of this steam is expanded isentropically to acondenser pressure of 0.03 bar, but 32% is bled from the turbine at apressure of 3 bar for process heating. If the condensate from the processheater 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.
Q4 Sketch on a T - s diagram the following cycle for a gas turbine:
(a) Isentropic compression
(b) Heat taken in at constant pressure p1
(c) Isentropic expansion through turbine 1 from pressure p1 down to intermediate pressure p3
(d) Reheat at pressure p3
(e) Isentropic expansion from pressure p2, through turbine 2, down to final pressure