Engineering Answers

10. A supercritical power generates steam at 25 Mpa and 560℃. The condenser pressure is 7 kpa. Determine

the exit quality of steam if it expands through a turbine in this power plant.

9. Steam enters a turbine at 1.4 Mpa and 320℃. The turbine internal efficiency is 70%, and the total requirement is 800 kw. The exhaust is to the back pressure system, maintains at 175kpa. Find the stean flow rate.

8. A steam power plant operates on the Rankine cycle. The steam enters the turbine at 7 Mpa and 550℃ with a velocity of 30 m/s. it discharges to the condenser at 20 kpa with a velocity of 90 m/s. Calculate the net work in kw for a flow of 37.8kg/s.

7. A superheat steam Rankine cycle has turbine inlet conditions of 17.5 Mpa and 530℃ expands in a turbine to 0.007 Mpa. The turbine and pumps polytropic efficiencies are 0.9 and 0.7 respectively, pressure losses between pump and turbine inlet are 1.5 Mpa. What should be the pump work in KJ/kg?

6. A throttling calorimeter is connected to the superheated steam line supplying steam to the auxiliary feed pump on a ship. The line pressure measures 2.5 Mpa. The calorimeter pressure is 110 kpa and 150oC. Determine the entropy of the steam line.

5. A steam condenser receives 10 kg/s of steam with an enthalpy of 2570 KJ/kg. steam condenses into a liquid and leaves with an enthalpy of 160 KJ/kg. Cooling water, passes through the condenser with temperature increases from 13 degrees C to 24 degrees C. Calculate the water flow in kg/s.

4. Steam is delivered to turbine at 5.4 Mpa and 600℃. Before condensation at 31℃, steam is extracted for feedwater heating at 0.6 Mpa. For an ideal regenerative cycle, find the thermal efficiency.

3. In an ideal reheat cycle, the steam throttled condition is 8 Mpa and 480℃. The steam is then reheated to 2 Mpa and 460℃. If turbine exhaust is 60℃, determine cycle efficiency.

2. A Rankine cycle has an initial mass of liquid flowing at 10 kg at 75℃. If final enthalpy is 379.6 KJ, find the change of the system.

1. 150 grams of water at 75℃ is heated at constant pressure. The water is completely vaporized, what is the heat added?