Effect of Blowing Ratio on Turbine Blade Air Film Cooling Under Different Engine Conditions

Abstract

Under different working conditions of the aeroengine, the rotating speed of the turbine blades is diverse, and this causes the high-temperature gas mainstream to impact the turbine blades at disparate angles of attack. In order to explore the film cooling mechanism of the pressure surface and suction surface of aeroengine turbine blade at unusual speed, a 3D model of the turbine blades and internal runners is constructed, which refers to Pratt & Whitney PW4084 primary HPT blade. In this model, the high-temperature gas mainstream is set to attack the turbine blades through three distinct angles, the turbine blade air film cooling model is established, and the numerical simulation is conducted at the different blowing ratios. The results showed that the angle of impact (rotational speed) is the key factor affecting the cooling efficiency of the blade. The cooling effect of the suction surface is the best under the positive attack, however, the cooling effect of the pressure surface under the negative attack angle is the first-rate. With the increase of the speed, the surface temperature of the top and tail of the blade pressure surface will gradually decrease, and as the speed reduces, the surface temperature of the lower part of the suction surface of the blade will slightly increase. Finally, under three different attack angles, the cooling efficiency of the air film on the surface of the blade will augment with the increase of the blowing ratio.