Investigation the influence of the number and configuration of fins on the hydrothermal behavior of a double-pipe heat exchanger

The current study targets improving the overall performance of a Double Pipe Heat Exchanger (DPHE), along with developing a correlation equation to predict the Nusselt number and friction factor. The effect of both the number and configuration of fins has been studied numerically in detail using ANSYS Fluent 2022 R1 software. The numbers of fins considered under study were 4, 6, 8, and 10, while the fin configurations were longitudinal and wavy. To verify the numerical results, a comparison of computational and experimental results was done for the traditional model; this comparison showed excellent agreement between them. Furthermore, the outcomes have shown that the overall performance of a DPHE is influenced by the number and configuration of fins. The results show that the optimum model among all models under study is a wavy fin configuration with 8 fins with an overall response of 1.33 as compared to the traditional model. In addition, four equations were developed using the numerical findings and analysis of multiple regression to predict the Nu number and friction factor as functions of the Reynolds Number (Re), Prandtl Number (Pr), number of fins (No. fin), length of pitch ($L_p$) and inner pipe length ($L_{\mathrm{an}}$). The accuracy of the Nu number and friction factor equations for the longitudinal fins is 98.96 % and 96.17 %, respectively, while that for the wavy fins is 99.18 % and 97.96 %, respectively. As a result, this study can accurately depict the overall response of a DPHE.