Mechanical Engineering Answers

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?

5. Compute for the enthalpy, internal energy, and entropy of steam at 72oC and 93% quality. Please explain the answer?

The specific heat at constant pressure of 1kg fluid undergoing a non –flow constant pressure

process is given by:

𝐶𝑝 = [2.5 +

40

𝑇+20]kJ/kg-℃ where T is in degrees centigrade. The pressure during the process

is maintained at 2 bar and volume changes from 1m3

to 1.8 m3

and temperature changes from

50℃ to 450℃. Determine (a) heat added (b) work done (c) change in internal energy (d) change

in enthalpy

Two equal 5-module, 20 degree gears mesh

together such that the addendum circle of each

gear passes through the interference point of the

other. If the contact ratio is 1.622, calculate the

number of teeth and the outside radius on each

gear.