A double-pipe heat exchanger is designed as an engine oilcooler. The flow rate of oil is 5 kg/s, and it will be cooled from60°C to 40°C through annulus (ID = 0.10226 m, OD = 0.1143 m). Seawater flows through the tubes (ID = 0.02664 m, OD = 0.03340 m) andis heated from 10°C to 30°C. The number of bare tubes in theannulus is 3, and the length of the hairpin is 3 m. Assume that thetube wall temperature is 35°C. Design calculations give the numberof hairpins as 85. Allowable pressure drop in the heat exchangerfor both streams is 20 psi. Is this design acceptable? Outline yourcomments.
