Reference no: EM13620096

1. A Diesel cycle operates with a compression ratio of 15, and a cutoff ratio of 2.5. What is the rate of heat input required for this cycle to produce 223.8 kJ/s? (for air use: k=1.4)

a) 227 kJ/s

b) 386 kJ/s

c) 438 kJ/s

d) 556 kJ/s

2. A gas turbine utilizes two stages of compression, two stages of expansion, intercooling, reheating, and regeneration. What is the thermal efficiency of this gas turbine using the following data: T2 = 446 K and T7 = 808 K, T3 = T1 = 300 K, T10 = T4 = T2 = 446 K, T5 = T7 = T9 = 808 K, and T6 = T8 = 1200 K.

a) 0.22

b) 0.41

c) 0.63

d) 0.72

3. The enthalpies around an ideal Rankine cycle with an open-feedwater-heater are: h1 = 340.5 kJ/kg, h2 = 340.6 kJ/kg, h3 = 444.3 kJ/kg, h4 = 447.2 kJ/kg, h5 = 3115.3 kJ/kg, h6 = 2479.9 kJ/kg, and h7 = 2344.1 kJ/kg. What percentage of the mass flow rate passing through the boiler is bled from the turbine for open-feedwater-heater?

a) 4.85 %

b) 7.31 %

c) 10.6 %

d) 13.2 %

4. The enthalpies at various states in an ideal Rankine cycle with an open-feedwater-heater are: h1 = 340.5 kJ/kg, h2 = 340.6 kJ/kg, h3 = 444.3 kJ/kg, h4 = 447.2 kJ/kg, h5 = 3115.3 kJ/kg, h6 = 2479.9 kJ/kg, and h7 = 2344.1 kJ/kg. What is the thermal efficiency of this cycle?

a) 24.6 %

b) 28.6 %

c) 32.6 %

d) 36.6 %

5. The enthalpies at various states in a simple vapor-compression refrigerator cycle are:

h1 = 237.14 kJ/kg, h2 = 283.10 kJ/kg, and h3 = h4 = 115.76 kJ/kg. What is the coefficient of performance of this device

a) 2.64

b) 2.93

c) 3.26

d) 3.69

6. An ideal R-134a, dual compressor vapor-compression refrigerator system uses a flash chamber to separate the vapor in the evaporator feed line. The enthalpies of refrigerant at various states are: , h1 = 235.31 kJ/kg, h5 = h6 = 125.26 kJ/kg, h3 = 252.32 kJ/kg, and h7 = h8 = 62.00 kJ/kg. What fraction of the mass flow rate passing through the evaporator.

a) 0.8

b) 1.0

c) 1.2

d) 1.5

7. At one location in a nozzle, the air enthalpy is 401 kJ/kg and the air velocity is 400 m/s. What is the stagnation enthalpy (based on temperature dependent specific heats) of the air at this location?

a) 300 kJ/kg

b) 357 kJ/kg

c) 470 kJ/kg

d) 481 kJ/kg

8. At one location in a nozzle, the air temperature is 400 K and the air velocity is 450 m/s. What is the Mach number at this location? (for air: k=1.4 and R=287 J/kg K)

a) 0.97

b) 1.12

c) 1.37

d) 2.02