Heat transfer mechanism of different vortex generators arrangements embedded in heat exchange tubes

Abstract

Heat exchange is widely used in many fields to improve heat transfer efficiency and save energy, while longitudinal vortex generator (VG) is widely used in many heat transfer heat exchangers. In this work, the effect of VGs with different numbers and different pitch ratios (PR) on the heat transfer characteristics in the tube was studied numerically. The results show that when the fluid flows through the VG, the reflux region will be generated, and the fluid velocity in the reflux region will be inhibited, resulting in uneven temperature distribution and increased Nu. When multiple VGs are arranged in a row, the number of vortices is increased, and the area affected is increased. This improves the overall heat transfer performance. With the decrease of PR, the number of VG rows increases, and the heat transfer performance increases first and then decreases with the decrease of PR.