Internal Cooling Passage Heat Transfer Near the Entrance to a Film Cooling Hole: Experimental and Computational Results

Abstract

Detailed heat transfer measurements were made near the entrance to a single film cooling hole using a transient liquid crystal technique in a large scale (100X) model. The hole inclination angle and flow extraction rate were varied across a range representative of actual engine conditions. Local values of heat transfer were found to exceed 6 times the levels associated with fully developed, turbulent channel flow. The region of maximum heat transfer enhancement occurred downstream of the hole entrance. Computational and experimental flow diagnostics were performed to investigate the mechanisms responsible for the observed heat transfer distributions. The removal of the upstream boundary layer and the downwash created by a vortex pair were found to be important phenomena.