EFFECTS OF LONGITUDINAL VORTEX GENERATORS ON HEAT-TRANSFER AND FLOW LOSS IN TURBULENT CHANNEL FLOWS

The influences of four types of longitudinal vortex generators (delta wing, rectangular wing, delta winglet pair and rectangular winglet pai r) on heat transfer and flow loss in turbulent channel flows are inves tigated in the present work. A numerical solver, of the Navier-Stokes equations, based on the MAC algorithm, has been extended with the k-ep silon turbulence model for this study. The results show that the longi tudinal vortices produced by the vortex generators elevate significant ly the level of turbulence kinetic energy in the flows and strongly di sturb the thermal boundary layer. The mean heat transfer rate can be i ncreased by 16-19% with the vortex generators for an area of channel w all which is 30 times larger than the vortex generator area. The ratio of heat transfer enhancement and flow loss increase indicates better performance for the rectangular winglet pair.