Film Cooling Using Antikidney Vortex Pairs: Effect of Blowing Conditions and Yaw Angle on Cooling and Losses

Abstract

A filmcooling configuration generating an antikidney vortex pair is studied. The configuration features cylindrical cooling holes inclined at an angle of خ±=35  deg and arranged in two spanwise rows with rowwise alternating yaw angles آ±خ². Results of several largeeddy simulations are presented with varying blowing conditions and yaw angles. The effects on the achieved cooling and the generated losses are studied. The filmcooling Reynolds number (based on the fully turbulent hot boundary layer along a flat plate and the cooling hole diameter) is 6570 and the Mach number is 0.2. The density as well as massflux ratios (DR and M) range from 1 to 2 and the yaw angles from خ²=آ±30  deg to آ±60  deg. We identify scaling parameters and explain relevant mechanisms. Moreover, the flow field is subdivided into three regions featuring different physical mechanisms: the singlejet, the jetinteraction, and the diffusion region. A strong antikidney vortex pair occurs for high momentum ratios I. For the highest ratio, I = 2.3, our configuration may provide even better effectiveness than cooling with particular fanshaped holes.