Effect of compound corrugation on heat transfer performance of corrugated tube

Corrugation parameters are the key factors affecting the heat transfer performance of the corrugated tube. The purpose of this study is to investigate the impact of compound corrugation on the heat transfer performance of corrugated tubes. First, the computational fluid dynamics (CFD) approach based on realizable k -epsilon model is adopted to analyze the mechanism of the difference between simple corrugation and compound corrugation on the heat transfer performance of corrugated tubes. Subsequently, the effects of compound corrugation width (W2) and compound corrugation depth (H2) on the heat transfer performance of corrugated tubes are carefully studied in the 5000-30,000 Reynolds number range. Qualitative and quantitative comparisons of velocity, streamline, turbulent kinetic energy, and temperature are made to demonstrate how compound corrugation affects the heat transfer performance of corrugated tubes. The results show that compared with simple corru-gation, compound corrugation will induce stronger fluid mixing in the near-wall due to the superposition effect, as well as providing more substantial heat transfer improvement. The average values of TKE and Nu in the CCT are 22% and 10.1% higher than those in the SCT respectively. Additionally, the heat transmission efficacy of CCT improves with the increase of compound corrugation width (W2) and compound corrugation depth (H2). The highest Nusselt number ratio of 2.15 can be obtained when W2/D = 0.3 and H2/D = 0.05. The results of this study provide support for the design of compound corrugations to improve the heat transfer performance of the corrugated tube, and further research is still needed to understand the influence law of compound corrugation in detail.