Engine oil is to be cooled down from 95C to 75C to be used as a lubricant; it has a constant flow rate of 500 kg/hr. Water at 25 C is to be used as the coolant.
For economical pumping, the water velocity must be kept less than 2 m/s and the oil velocity to 1 m/s.
Develop a double pipe heat exchanger, specifying velocities, mass flowrates, length and inlet and outlet temperatures. Also calculate the pressure drop for each fluid.
Use schedule-40 wrought steel pipe in standard dimensions for both the inner and outer pipes.
Use hydraulic diameter to analyze the annular flow.