Effect of compound angle injection on flat surface film cooling with largestreamwise injection angle

Film cooling measurements are presented over a flat surface through a singl e row of discrete holes angled 55 degrees along the streamwise direction. T he holes are angled 0 degrees and 60 degrees in the lateral direction to st udy the effect of compound angle injection. Detailed heat transfer coeffici ent enhancement and film effectiveness distributions are presented for the entire region from downstream of the holes to distances far downstream at a bout X/d = 20. Tests were conducted in a low speed wind tunnel. The mainstr eam flow Reynolds number based on hole diameter is around 9500 and the free -stream turbulence intensity is set at 11%. Results are presented for three blowing ratios of 0.5, 1.0, and 1.5 and a coolant-to-mainstream density ra tio of 1.0. A transient liquid crystal technique will be used to measure bo th the local heat transfer coefficient and film effectiveness results simul taneously. The technique uses two similar tests to resolve the heat transfe r coefficient and film effectiveness. The detailed heat transfer coefficien t and film effectiveness contours provide a clear understanding of the jet- mainstream interactions for different hole orientations with large streamwi se angle injection. Results show that adding a compound angle to a hole wit h large streamwise angle produces significant variations in the detailed fi lm effectiveness distributions and enhances local heat transfer coefficient s. (C) 2001 Elsevier Science Inc. All rights reserved.