Experimental Flow Structure Investigation of Compound Angled Film Cooling

Abstract

The experimental investigation of film-cooling flow structure provides reliable data for calibrating and validating a 3D feature based computational fluid dynamics (CFD) model being developed synchronously at the ETH Zurich. This paper reports on the flow structure of a film-cooling jet emanating from one hole in a row of holes angled 20 deg to the surface of a flat plate having a 45 deg lateral angle to the freestream flow in a steady flow, flat plate wind tunnel. This facility simulates a film-cooling row typically found on a turbine blade, giving engine representative nondimensionals in terms of geometry and operating conditions. The main flow is heated and the injected coolant is cooled strongly to obtain the requisite density ratio. All three velocity components were measured using a nonintrusive stereoscopic particle image velocimetry (PIV) system. The blowing ratio and density ratio are varied for a single compound angled geometry, and the complex three dimensional flow is investigated with special regard to vortical structure.