In the following question you may ignore changes in elevation and velocity of the fluid. (a) In a steam power plant liquid water enters the boiler at a temperature of 40°C and exits as wet steam at a pressure of 15 bar with a dryness fraction of 0·95. Find the heat transfer per kg to the steam. (b) The wet steam passes through a superheater and emerges at a pressure of 15 bar and temperature of 300 °C. It then passes through a turbine, generating 400 kW of power as it does so, and comes out as wet steam at a pressure of 1 bar. The mass flow rate is 0·57 kg/s. There is no heat loss from the turbine. (i) Show that the exit specific enthalpy is about 2337 kJ/kg. (ii) Find the dryness fraction of the steam at the turbine exit. (c) Sketch the T-S diagram for the Rankine (steam plant) cycle and describe the processes. Also indicate on the diagram the points corresponding to the inlet and outlet of the boiler, superheater and turbine.
In the following question you may ignore changes in elevation and velocity of the fluid.
(a) In a steam power plant liquid water enters the boiler at a temperature of 40°C and exits as wet steam at a pressure of 15 bar with a dryness fraction of 0·95. Find the heat transfer per kg to the steam.
(b) The wet steam passes through a superheater and emerges at a pressure of 15 bar and temperature of 300 °C. It then passes through a turbine, generating 400 kW of power as it does so, and comes out as wet steam at a pressure of 1 bar. The mass flow rate is 0·57 kg/s. There is no heat loss from the turbine.
(i) Show that the exit specific enthalpy is about 2337 kJ/kg.
(ii) Find the dryness fraction of the steam at the turbine exit.
(c) Sketch the T-S diagram for the Rankine (steam plant) cycle and describe the processes. Also indicate on the diagram the points corresponding to the inlet and outlet of the boiler, superheater and turbine.
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