Heat transfer enhancement downstream of vortex generators on a flat plate
This investigation was conducted in order to better understand the augmentation of forced convective heat transfer when a single row of counter-rotating vortex blades is attached to a flat surface. The major emphasis of the work is to study the way in which vortex generators augment the heat transfer coefficient of an initially-laminar boundary layer over a flat, constant-heat-flux surface exposed to favorable free-stream pressure gradients. Particular emphasis is placed on the relationship between the geometry of vortex generators and the augmentation of local and overall heat transfer coefficients. The behavior of the boundary layer downstream of vortex generators is partially explored;This dissertation includes results of an experimental investigation that indicates the amount of heat transfer enhancement depends on the vortex blade height and arrangement on the plate surface. The local enhancement of heat transfer coefficient was increased up to 300% over that for a plain flat plate mainly because of high turbulence produced over the region adjacent to the plate surface, resulting in increased mixing of the slower fluid near the plate surface with the free stream. A set of guidelines for the design of more efficient surface with vortex generators was proposed.