Showing papers by "Liang-Bi Wang published in 2006"

Numerical study of interactions of vortices generated by vortex generators and their effects on heat transfer enhancement

Abstract: Vortex generators (VGs) can generate developing boundary layers, swirl, and flow destabilization, and can be used to enhance heat transfer. In compact heat exchangers with VG enhancement, there are tubes and VGs, all of them will generate vortices, and these vortices interact. In this article, a numerical study of interactions of vortices generated by VGs and the effects of such interactions on heat transfer enhancement of flat tube bank fins are carried out. The results show that for some cases, interactions of vortices generated by VGs located upstream and downstream will take place, and the heat transfer enhancement on the fin surface is weakened.

The optimal fin spacing for three-row flat tube bank fin mounted with vortex generators

Abstract: To reduce the size and the weight of heat exchangers, vortex generators (VGs) were punched on fin surface to improve the fin heat transfer performance. This paper is focused on the optimal fin spacing for three-row flat tube bank fin mounted with VGs. The results show, for commonly used fin materials and fin thickness, the optimal fin spacing is about 2 mm in industrial application for the configuration of tube bank fin studied.

The Optimum Angle of Attack of Delta Winglet VortexGenerators on Heat Transfer Performance of Finned Flat Tube Bank with Considering Nonuniform Fin Temperature

Abstract: To investigate the effects of the angle of attack of delta winglet vortex generators (VGs) on heat transfer performance and pressure drop penalty of finned flat tube bank, local and average heat transfer characteristics were studied by using analogy between heat and mass transfer with naphthalene sublimation experiments. In order to consider nonuniform fin temperature, the heat transfer rate from fin surfaces was investigated by solving the conduction equation in the fin with a Finite Volume Method on curvilinear coordinate systems based on experimental results of local heat transfer. Three angles of attack (> = 25°, 35°, 45°) are investigated. Without considering the nonuniform fin temperature, increasing the angle of attack, average Nusselt number and friction factor are increased, the heat transfer enhancement on fin surface without mounted VGs is reduced, but the heat transfer enhancement on fin surface mounted with VGs is less affected. Considering the nonuniform fin temperature, the heat transfer en...