Numerical and experimental determination of flow structure and heat transfer effects of longitudinal vortices in a channel flow

Abstract

Longitudinal vortices have enormous utility for flow control. Longitudinal vortices are also capable of producing beneficial effects in transport enhancement. The vortices disrupt the growth of the boundary layer and serve ultimately to bring about enhancement of heat transfer between the fluid and its neighboring surface. The present study determines the flow structure, in detail, behind a winglet type vortex generator placed in a fully developed laminar channel flow. The flow structure is complex and consists of a main vortex, a corner vortex and induced vortices. Experiments are performed in order to corroborate the numerical predictions of the flow structure. The purpose of this study is to show the performance of a delta winglet type vortex generator in improving heat transfer. The conclusions that are drawn identify plausible choice regarding the optimal angle of attack of the vortex generator. Such vortex generators show great promise for enhancing the heat transfer rate in plate-fin crossflow heat exchangers.