Q18. Air enters the compressor of a gas turbine plant at a temperature of 27°C and leaves at a temperature of 280°C. It then enters the combustion chamber, from which hot gas leaves at a pressure of 6.5 bar and a temperature of 1100°C. The hot gas then enters the turbine and expands to a pressure of 1.02 bar with isentropic efficiency 85%. The turbine exhaust passes to a heat exchanger where heat is transferred to evaporating steam. The gas leaves the heat exchanger at a temperature of 400°C. The steam enters as saturated liquid at a pressure of 28 bar, and leaves with a dryness fraction of 0.98. The effective surface area for heat transfer is 18 m2, and the overall U-value is 2000 W/m2 K. Determine EACH of the following:
(a) The rate of heat transfer in the heat exchanger
(b) The mass flow rate of steam
(c) The gross power output of the turbine
(d) The overall thermal efficiency of the plant (including the heat transferred to the steam as part of the useful output).
Note: For air, Cp = 1.005 kJ/kg K
For hot gas, Cp = 1.15 kJ/kg K and γ = 1.35
Please buy a membership plan and login via our app to view answers.
Download our App
