PERFORMANCE EVALUATION OF A VORTEX GENERATOR HEAT-TRANSFER SURFACE AND COMPARISON WITH DIFFERENT HIGH-PERFORMANCE SURFACES

A comparative assessment of five different heat transfer configurations for operation in compact heat exchangers is presented. The configurations under consideration are four standard heat exchanger surfaces-two plain fin, an offset strip and a louvered fin geometry-and one surface with so called vortex generators for heat transfer augmentation. In the case of the standard surfaces, the basic performance characteristics in the form of heat transfer and friction data versus the Reynolds number have been taken from published experimental results. In the case of the vortex generator surface, the performance characteristics have been derived from a numerical prediction of the flow and temperature field in a closely spaced parallel plate channel with vortex generators in the form of delta wings mounted on the channel walls. In comparison to the plain fin surface with a rectangular cross section, the vortex generator surface shows best performance characteristics allowing a reduction in heat transfer surface area of 76%, for fixed heat duty and for fixed pumping power.