2an oil pump is drawing 44 kw of electric power while pumping oil withrho=860kg/m3at a rate of 0.1m3/s. the inlet and outlet diameters of the pipe are 8 cm and 12 cm, respectively. if the pressure rise of oil in thepump is measured to be 500 kpa and the motor efficiency is 90 percent, determine the mechanical efficiencyof the pump.

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]