A mass of 0.1 kg of water, initially at 250 oC and 500 kPa is contained in a rigid container. The water is allowed to cool to the ambient temperature of 25oC. (a) Sketch the process on the P-v ant T-v diagrams, showing the saturation lines, as well as the isotherms passing through the initial and final states. Label the last with the appropriate temperature values, and label all relevant points. (b) Calculate the heat transfer during the process. (c)Calculate the total entropy change for the system and its surroundings.

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

Coiled springs ought to be very strong and stiff. si3n4 is a strong, stiff material. would you select this material for a spring? explain.

Give heat transfer applications for the following, (i) gas turbines (propulsion) ) gas turbines (power generation). (iii) steam turbines. (iv) combined heat and power (chp). (v) automotive engines