Thermodynamics steam | Science homework help
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 of 500°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. Neglect feed pump work.
(b) If the isentropic efficiency of the steam turbine in part (a) above is 0.82, 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 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.
Q4.4. 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 p2.