Air at 20°c (1 atm) enters into a 5-mm-diameter and 10-cm long circular tube at an average velocity of 5.2 m/s. the tube wall is maintained at a constant surface temperature of 160°c. determine the convection heat transfer coefficient and the outlet mean temperature. evaluate the air properties at 50°c. the properties of air at 50°c are:

Acompressor receives the shaft work to decrease the pressure of the fluid. a)- true b)- false

Athin walled concentric tube exchanger is used to cool engine oil from 160°c to 60°c with water that is available at 25°c acting as a coolant. the oil and water flow rates are each at 2 kg/s, and the diameter of the inner tube is 0.5 m and the corresponding value of the overall heat transfer coefficient is 250 w/m2. oc. how long must the heat exchanger be to accomplish the desired cooling? cpwater=4.187 kj/kg-candcpengine el=2.035 kj/kg·°c, oil . 120]

Asteam is contained in a rigid tank with a volume of 1 m3. initially, the pressure and temperature are 7 bar and 500 oc, respectively. the temperature drops due to cooling process. determine: (1) the temperature at which condensation begins in °c, (2) the fraction of the total mass that has condensed when the pressure decreased to 0.5 bar. (3) the volume in m3 occupied by saturated liquid at the final state?