Impingement Heat Transfer Enhancement in Crossflow by V-Shaped Protrusion Vortex Generator

This paper numerically studies the effect of a V-shaped protrusion vortex generator on flow and heat transfer of impingement cooling in crossflow. The simulations are performed by solving three-dimensional steady Reynolds-Averaged Navier-Stokes equations with shear stress transport k-Omga turbulence model. Four crossflow ratios, five locations and heights of the V-shaped protrusion vortex generator are discussed. Results indicate that (1) the V-shaped protrusion vortex generator effectively improves the peak value of Nusselt number and widens the high heat transfer range at the crossflow ratios of 0.3 and 0.4 due to the decrease of actual crossflow ratio and the generation of an additional counter-rotating vortex pair, while it has little effect at the crossflow ratios of 0.1 and 0.2; (2) as the distance between vortex generator and jet hole increases from 2.5 to 4.5 times of diameter, the Nusselt number increases and the jet total pressure drop decreases, thus the thermal performance factor increases with a maximum increasement of 22.57%; and (3) the Nusselt number increases with the increase of vortex generator height, and when the crossflow ratio is large enough, the impingement heat transfer can be improved even that a shallow V-shaped protruding vortex generator is used.