The evaporator of a refrigeration cycle is basically a heat exchanger in which air is cooled by a refrigerant evaporated by absorbing heat from the air. R-134a enters an evaporator at 140 kPa with a quality of 10% and a flow rate of 0.01 m3/s. The refrigerant leaves the evaporator at the same pressure superheated by 8.77oC. The air flow rate is 10 kg/s. Determine (a) the rate of heat absorbed from the air and (b) the temperature change of air.

Amass of m 1.5 kg of steam is contained in a closed rigid container. initially the pressure and temperature of the steam are: p 1.5 mpa and t 240°c (superheated state), respectively. then the temperature drops to t2= 100°c as the result of heat transfer to the surroundings. determine: a) quality of the steam at the end of the process, b) heat transfer with the surroundings. for: p1.5 mpa and t 240°c: enthalpy of superheated vapour is 2900 kj/kg, specific volume of superheated vapour is 0. 1483 m/kg, while for t 100°c: enthalpy of saturated liquid water is 419kj/kg, specific volume of saturated liquid water is 0.001043m/kg, enthalpy of saturated vapour is 2676 kj/kg, specific volume of saturated vapour is 1.672 m/kg and pressure is 0.1 mpa.

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

The higher the astm grain size number, the finer the gran is. a)-true b)-false