5.33 A DPHX is made of a 6-nom sch 80 outer pipe and a 4-nom sch 40 inner pipe.

The fluid in the annular space is liquid water that has a volumetric flow rate of 20 L/s and an average temperature of 40°C. The fluid in the inner tube is a 40% ethylene glycol solution at an average temperature of 20°C and flowing at 15 L/s. Determine the Reynolds numbers of the flow in the pipe and the annulus for

a. Friction calculations

b. Heat transfer calculations