5.32 The outer pipe in a DPHX is 4-nom sch 40 commercial steel. The inner tube is 3-std type K copper. The fluid inside the inner tube is flowing at a volumetric rate of 60 gpm and the fluid in the annulus flows at 40 gpm. For this heat exchanger determine

a. Hydraulic diameter of the annulus (ft)

b. Equivalent diameter of the annulus (ft)

c. Velocity of the fluid in the inner tube (ft/s)

d. Velocity of the fluid in the annulus (ft/s)