Numerical analysis of thermal-hydraulic comprehensive performance of composite corrugated tubes with different cross-section shapes

Composite corrugation is a structure transformed from traditional corrugation to improve the thermal-hydraulic comprehensive performance (THCP) of corrugated tubes. However, compared to simple corrugations, the mechanism by which composite corrugations enhance THCP is still unclear. Therefore, in this work, numerical simulations are performed within the Reynolds number (Re) range of 5000-20,000 to evaluate the mechanism of composite corrugation strengthening THCP. The distributions of flow velocity, streamline, turbulent kinetic energy (TKE), pressure, and normalized force are used to reveal the differences in the effects of simple and composite corrugations on THCP. In addition, the influence of composite corrugation cross-sections and distribution forms on THCP has been explored in detail. The results indicate that increasing the impingement of the fluid on the tube wall, disrupting the fluid boundary layer, and expanding the range of secondary flow are the main mechanisms by which composite corrugations further strengthen THCP compared to simple corrugations (CT-SC). The THCP of composite corrugation (CT-CC-A-F) can be increased by 31.5% at Re = 20,000 compared to CT-SC. Composite corrugations with different cross-sections cause differences in THCP due to their varying effects on the distribution of secondary flow and the impingement of the fluid on the tube wall. The difference in the influence of composite corrugation distribution forms on THCP is still caused by the difference in the impingement of the fluid on the tube wall. This work can provide a reference for the design of composite corrugations to achieve better THCP.