期刊名称：International Journal of Energy and Environment
印刷版ISSN：2076-2895
电子版ISSN：2076-2909
出版年度：2014
卷号：5
期号：3
页码：197-206
出版社：International Energy and Environment Foundation (IEEF)
摘要：Spiral tubes have been reported to be able to improve the heat transfer performance of the fluid flowing through, which is traditionally believed to be caused by the helix structure. In this literature, however, the mechanism of the heat transfer enhancement of spiral tubes was studied experimentally in terms of the control factors of Dean vortices such as Reynolds number, fluid viscosity and curvature ratio. Meanwhile, the torsion of the spiral tube was also taken into consideration. Experiments were carried out under constant wall temperature condition with one straight copper tube and 7 kinds of spiral copper tubes. The results showed that the Nusselt number of the flow in spiral tubes increases with Reynolds number, viscosity and curvature ratio, but changes anomalously with the torsion. And it also clearly revealed that the pressure drop for spiral tubes increases with Reynolds number, curvature ratio and viscosity, while decreases with the torsion. In addition, the heat transfer performance of spiral tubes is apparently better than that of the straight tube. Based on the experiment results, the effect of Dean number on Nusselt number and pressure drop of the spiral tubes was determined, and the correlation equations of heat transfer enhancement by Dean vortices were obtained through multiple regression.
