Question 1

a) Determine the specific enthalpy of steam at 15 barand 275°C .

b) Determine the degree of superheat and entropy ofsteam at 10 bar and 380 °C.

c) A superheated steam at 12.5 MN/m2 is at 650°C.Determine its specific volume.

Question 2

A superheated steam at 24 bar and 500 °C expands atconstant volume until the pressure becomes 6 bar and the drynessfraction is 0.9. Calculate the changes in the internal energy ofsteam. Sketch the process in the form of a P-v diagram.

Question 3

Steam at 10 bar and 200 °C enters aconvergent-divergent nozzle with a velocity of 60 m/s and leaves at1.5 bar and with a velocity of 650 m/s. Assuming that there is noheat loss, determine the quality of steam leaving the nozzle.

Question 4

The temperature of feed water entering a boiler is 311°C and steam is produced at 40 bar and 500 °C. The rate of heattransfer to the surroundings is 35 kW. Determine the mass flow rateof the working fluid for a heat input to the boiler of 6 MW.

Question 5

Exhaust steam from a turbine enters a condenser with aspecific enthalpy of 2164 kJ/kg and a velocity of 75 m/s. Duringthe cooling process, the heat loss to the cooling water per kg ofworking fluid is 1680 kJ/kg. The condensate exits the system with avelocity of 12 m/s. Sketch a systems diagram for the condenser anddetermine the specific enthalpy of the working fluid at exit fromthe condenser.

Question 6

A steady flow boiler is supplied with water at 15kg/s, 100 bar pressure, and 200 °C. The water is heated and turnedinto steam. The steam leaves at 100 bar and 500 °C. Determine theheat transfer rate.