Lubricating oil enters the tubes of a heat exchanger at 74C and leaves at 34 C. The diameter of the tube is 50 mm and the oil flow through the tube at 2.5 m/s.
Input power to the system is 30 kW.
The specific heat capacity of the oil is 2.28 kJ/kgK and the density is 900 kg/m3. Determine;
a. The mass flow rate of the oil.
b. The thermal efficiency of this heat transfer process.