Film-Cooling Performance of Cylindrical and Cratered Holes Fed by a Perpendicular Crossflow

Recent studies have proven that a coolant crossflow influences the cooling performance of film-cooling gas turbine holes. The present paper evaluates the cooling performance for several innovative cratered film-cooling holes fed by a perpendicular crossflow channel. The flow fields, discharge coefficients, and the cooling effectiveness are analyzed and compared based on the results predicted by the methods of computational fluid dynamics (CFD) for cylindrical, concentric cratered, and contoured cratered holes. The investigated blowing ratio varies from 0.5 to 2.0. The ratio of the velocity at the crossflow channel inlet to the mainstream flow velocity is equal to 0.6. The study indicates that the character of the vortex pair and the velocity distribution depend on the specific hole shape and blowing ratio. A contoured cratered hole is shown to provide a higher cooling effectiveness than cylindrical and concentric cratered holes. In addition, it exhibits the highest discharge coefficients everywhere over the range of the blowing ratios studied.