ir at 200 kPa, 52°C, and a velocity of 355 m/s enters an insulated duct of varying cross-sectional area. The air exits at 100 kPa, 82°C. at the inlet, the cross-sectional area is 11.57 cm².

A- Air at 15°C and 1bar occupies 0.02 m³. The air is heated at constant volume until the pressure is 5bar, and then cooled at constant pressure back to the original temperature. Calculate the net heat flow to or from the air and the net entropy change. Sketch the process on a T-s diagram. (8.5marks)

Air is compressed in an adiabatic compressor. Inlet and outlet conditions are 120kPa, 30 oC and 20 m/s; 1.4 MPa, 530 oC and 80 m/s.  The surrounding air temperature is 25 oC. The inlet cross-sectional area is  0.013 m2. Assume Cp = 1005 J/kgK, R = 287 J/kgK, k = 1.4.   Enter the amount of heat loss due to irreversibility resulting from the heat transfer from the compressor in kW (correct up to one decimal place.)

A refrigerator transfers 1kJ of heat from a cold region at -20°c to hot region at 30°c. If COP of refrigerator is 4, total entropy change of region's will be:- A. 1.72 X 10-4 KJ/K B. 0.173 KJ/K Ос. 1.7 X 102 кЈ/К D. 0.9263 KJ/K