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In: Mechanical Engineering

Q. No.1A regenerative Rankine cycle operates with superheat, 2 stages of expansion and one open feed...

Q. No.1A regenerative Rankine cycle operates with superheat, 2 stages of expansion and one open feed heater. The cycle parameters are:  Boiler exit pressure 100 bar  Super heater exit temperature 600°C  Condenser pressure 0.1 bar  Turbine isentropic efficiency 100% Assume that the feed pump work can be neglected.

i. Determine the optimal inter-stage pressure by selecting the nearest value from the Saturated Water and Steam tables. i.e. do not interpolated between tabulated values. [2 marks]

ii. Sketch the feed heater layout, indicating the fluid streams entering and leaving the feed heater, undertake and energy balance on the feed heater and hence calculate the fraction of steam bled from the turbine. [2 marks]

iii. Calculate the plants thermal efficiency and its specific steam consumption.

iv. State clearly the thermodynamic reasons for the difference in performance between this cycle and similar cycle using a closed feed heater if the closed feed heater operated according the assumptions. What is the disadvantage of using an open feed heater? [2 marks]

v. Draw a schematic diagram of the plant layout and the associated thermodynamic cycle on a T-s diagram.

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