An experimental study of the deposition on plates with different film-cooling hole shapes

Abstract

The deposition of particles, such as sands, dusts and volcanic ashes, on turbines could reduce the aerodynamic and cooling performance of turbines. To investigate the effect of film-cooling with different hole shapes on the deposition, an experiment at about ambient temperature is designed, in which the test models are plates but with different film-cooling hole shapes and a kind of wax is atomized as the particles. The results show that for the blowing-ratio 3.0, the conical filmcooling hole could reduce the deposition rate 83% than the cylindrical film-cooling hole, and the covering-slot (CONSOLE) film-cooling hole could reduce the deposition rate 69%, although most deposition forms near the film-cooling holes for all film-cooling holes shapes. The film-cooling efficiency of the plate with the conical hole could be improved by up to 13% than cylindrical film-cooling hole, and the CONSOLE film-cooling hole could be improved by up to 21%. For the cylindrical film-cooling, at 2D ~ 15D after the film-cooling holes, the average cooling efficiency in the spanwise direction is improved after the experiment, and the maximum is increased by about 1.8% at X / D=6. From 15D to the tail, the average efficiency in the spanwise direction decreases by about 1.3% after the experiment. The average cooling efficiency of the conical hole is reduced by about 0.12% after the experiment, and the CONSOLE film hole structure has no obvious change. This study may be helpful for developing the technology of reducing the deposition and its harm on turbines.