Heat Transfer Enhancement From Single Vortex Generators

The effect of single full-body Vortex Generators (VGs) on heat transfer was investigated experimentally. The delta shaped devices with different geometries were examined in a rectangular channel for a Reynolds number range of 80,000 up to 600,000. The research included heat transfer as well as flow measurements. Detailed heat transfer results were obtained by a steady state thermochromic liquid crystal (TLC) method using heater foils. This full surface measurement shows heat transfer enhancement evoked by the longitudinal vortices produced by the VGs. Data for secondary flow structures were determined by Particle Image Velocimetry (PIV) measurements. The comparison of vortex position and heat transfer distribution shows that the local heat transfer maximum due to downflow regions of the secondary flow does occur at positions shifted slightly towards the centerline of the channel compared to the existing vortex cores. Experimental data for the flow field were also compared to numerical calculations using FLUENT.