Numerical investigation on the effect of a modified corrugated double tube heat exchanger on heat transfer enhancement and exergy losses

Abstract

In the present study, heat transfer and exergy losses in a double-tube heat exchanger with corrugated inner tubes were investigated. The inner tube of the heat exchanger with a diameter of 27 mm was made of copper and outer tube with a diameter of 54 mm was assumed insolated. First, semi-elliptical corrugations were created on the outer surface of inner tube of double tube heat exchanger. In addition, to delay the separation of flow, modified corrugations, consisting of a quarter of elliptic and an inclined line, were used, too. Results show that using corrugated tubes with semi-elliptical corrugations over inner tube of double-tube heat exchanger has significant effects on heat transfer and exergy losses. In addition, modified corrugations delay the separation of flow compared to semi-elliptical corrugations which increase heat transfer further. Also, results indicate that increase in heat transfer increases exergy losses.