Numerical and experimental investigation of the thermal performance of the double pipe-heat exchanger

The present study deals with improving the overall performance of a double-pipe heat exchanger (DPHE). Several configurations were considered to achieve this goal. Each type differs in the fin type that was used, namely longitudinal fins, split longitudinal fins (in in-line and staggered arrangements), and semi-helical fins in three angles (90̊, 180̊, and 270̊) and a constant heat flux applied to the inner surface of the internal tube (8000 W/m2). All models were created and numerically analyzed by the commercial software (ANSYS Fluent 2022 R1). The overall performance was studied in terms of Nusselt number (Nu), pressure drop, and thermal resistance. Two models were manufactured for the sake of verification under, namely the traditional model and the optimal model (Model D), and excellent agreement with numerical results was achieved. It was show that fin type has a significant effect on the overall performance of a DPHE. The best type among the considered fin types was the semi-helical eight-finned with angle 90̊ (model D), with an improve in overall performance and Nu number of 1.47% and 66.76% respectively. The study proved to be useful in accurate estimation of the overall performance of a DPHE.