Acounter-flow, double-tube (shell-and-tube) heat exchanger is used to cool the lubricating oil for large industrial gas turbine engine by cooling water which enters the heat exchanger at 30°c the copper inner tubes have a diameter of 2 cm and negligible thickness, while the inner diameter of the outer annulus (the shell) is 4 cm. water flows through the tube at a rate of 0.18 kg/s, and the oil through the shell at a rate of 0.12 kg/s. the inlet and outlet temperatures of oil are 95°c and 65°c, respectively. assume the tube wall resistance, fouling factors and heat loss to the surroundings are negligible. design the heat exchanger.

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.

If the thermal strain developed in polyimide film during deposition is given as 0.0044. assume room temperature is kept at 17.3 c, and thermal coefficient of expansion for the film and the substrate are 54 x 10^-6c^-1 and 3.3 x 10^-6c^-1respectively. calculate the deposition temperature.

Fluids at rest possess no flow energy. a)- true b)- false