Heat transfer study on a hybrid smooth and spirally corrugated tube

¹ Institute of Process Equipment, College of Energy Engineering, Zhejiang University, Hangzhou, 310027, PR China
² Department of Energy Sciences, Lund University, P.O. Box 118, SE-22100 Lund, Sweden

^* Corresponding author: qianjy@zju.edu.cn

Abstract

Corrugated tubes are widely used in a range of applications for heat transfer enhancement. The spirally corrugated tube has a better heat transfer performance than the smooth tube. In this paper, the heat transfer performance of a hybrid smooth and six-start spirally corrugated tube is studied. With a validated numerical model, the effects of the corrugation part length on the vortex in the downstream smooth tube are studied for a range of high Reynolds numbers, where the existence of the corrugation part can turn out the secondary flow and enhance heat transfer. Meanwhile, it is found that in the smooth part, the fluid flow part with whirling can reach a maximum length, even if the length of the corrugation part continuously increases. Thus a series of critical corrugation lengths can be obtained. This work can reveal the enhanced heat transfer mechanism of the hybrid smooth and spirally corrugated tube and be of interest to researchers in heat transfer issues of corrugated tubes.