Effects of a Vortex Generator Pair on Jet Impingement Heat Transfer in Cross-Flow

Abstract

Jet impingement cooling is commonly used in gas turbines. Usually the spent air from the upstream jets forms a cross-flow past the downstream jets, which degrades their heat transfer performance. In the present study, a new method was proposed to promote the jet penetration and enhance the impingement heat transfer. By placing a delta-winglet vortex generator pair (VGP) in the cross-flow upstream of the jet nozzle, it is found that the impingement heat transfer on the target wall is significantly enhanced. The stagnation region shifts upstream and expands compared to the original case. The stagnation and area-averaged Nusselt numbers also increased. The effects of the distance between the VGP and the jet nozzle l1 were also investigated. The optimal spacing l1 is suggested to be 4d, giving the best heat transfer performance. This study sheds new light on the enhancement of jet impingement heat transfer in a cross-flow.