Film Cooling Predictions for Cratered Cylindrical Inclined Holes

Abstract

Film cooling is studied for cylindrical holes embedded in craters. Different crater geometries are considered for a typical crater depth. Cratered holes occur when blades are coated with thermal barrier coating layers by masking the hole area during TBC spraying. The film performance and behavior will be different for the cratered holes compared to standard cylindrical holes. FLUENT is used to simulate film cooling for the different crater geoemtries and compared to baseline uncratered cylindrical holes. Film effectiveness is reduced by the cratering compared to earlier studies which had two-dimensional trenches instead of craters. The study is performed at a single mainstream Reynolds number based on free-stream velocity and film hole diameter of 11000 at one different coolant-to-mainstream blowing ratio of 1.0.