1. a) State three advantages of superheating in a Rankine vapour cycle. (3 marks) b) In...

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1. a) State three advantages of superheating in a Rankine vapour cycle. (3 marks) b) In an ideal reheat Rankine cycle, the steam enters the HP turbine at 50 bar and 400 °C. After isentropic expansion to 8 bar, the steam is reheated to 400 °C and then expanded in the LP turbine to the condenser pressure of 0.I bar. If the plant power output is 110 MW: i. Sketch the schematic layout and the T-s diagram for the cycle. ii. Determine the; pump power, mass flow rate of steam, cycle thermal efficiency, and the specific steam consumption. (17 marks) 2. a) State three effects of supersaturation in a nozzle. (3 marks) b) In a convergent-divergent nozzle, the steam enters at 20 bar and 350 °C and leaves at 2 bar. The inlet velocity to the nozzle is 100 m/s. Find the required throat and exit areas for a mass flow rate of 2 kg/s. Assume isentropic nozzle expansion. (17 marks) 3. A two stage velocity compounded impulse steam turbine has a mean blade speed of 140 m/s. The steam leaves the nozzle with a velocity of 720 m/s at an angle of 20°. The exit angles of the first row moving blade, fixed blade, and second row moving blade are 25°, 25° and 30° respectively. For a blade velocity coefficient. of 0.92 for all blades and flow rate of 6 kg/s determine; a) The power output b) The diagram efficiency. (20 marks) 1. a) State three advantages of superheating in a Rankine vapour cycle. (3 marks) b) In an ideal reheat Rankine cycle, the steam enters the HP turbine at 50 bar and 400 °C. After isentropic expansion to 8 bar, the steam is reheated to 400 °C and then expanded in the LP turbine to the condenser pressure of 0.I bar. If the plant power output is 110 MW: i. Sketch the schematic layout and the T-s diagram for the cycle. ii. Determine the; pump power, mass flow rate of steam, cycle thermal efficiency, and the specific steam consumption. (17 marks) 2. a) State three effects of supersaturation in a nozzle. (3 marks) b) In a convergent-divergent nozzle, the steam enters at 20 bar and 350 °C and leaves at 2 bar. The inlet velocity to the nozzle is 100 m/s. Find the required throat and exit areas for a mass flow rate of 2 kg/s. Assume isentropic nozzle expansion. (17 marks) 3. A two stage velocity compounded impulse steam turbine has a mean blade speed of 140 m/s. The steam leaves the nozzle with a velocity of 720 m/s at an angle of 20°. The exit angles of the first row moving blade, fixed blade, and second row moving blade are 25°, 25° and 30° respectively. For a blade velocity coefficient. of 0.92 for all blades and flow rate of 6 kg/s determine; a) The power output b) The diagram efficiency. (20 marks)

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QUESTION 1 QUESTION2 QUESTION 3 a Advanta go of supor heating Increase the the omal efficiency of ... View the full answer