Flow and Heat Transfer Characteristic on the Downstream Surface in case of Solid Body and Vortex Generating Jet Turbulators

Abstract

In this research, the flow and heat transfer characteristics inside wind tunnel produced circulation flow were studied using computational fluid dynamics. Four types of circulation flow generators (2 types of solid turbulators and two types of vortex generating jets, VGJs, turbulators): (1) rectangular fin mounted crossing the flow, (2) a row of pins mounted perpendicularly on the surface, (3) a slot jet, and (4) a row of circular jets were attached prior heat transfer surface inside constant flow velocity tunnel. The tunnel inlet air velocity was set at 5 m/s with uniform flow condition. In case of VGJs, the velocity ratios, which was defined as the ratio of a jet velocity to a mainstream velocity, VR, of 0.33, 0.6, 1.0, 1.3, were simulates to investigate the heat transfer of downstream surface under constant heat flux condition. The results show that the use of VGJs turbulators can enhance heat transfer as the similar to the use of solid turbulators. It is due to circulating flow along downstream direction that is generated from both turbulators.