Film Cooling Numerical Study Of Transonic Turbine Cascade

Film cooling technology is one of the most widely used techniques in gas turbine engine turbine blade cooling technologies. Usually between turbine blades is subsonic flow, film cooling technology under subsonic conditions have been more in-depth studied. With the increase of single-stage turbine PRessure ratio, the flow between the turbine blades gradually transformed into transonic, and even reached supersonic. Turbine blade film cooling technology under the conditions of transonic and supersonic becomes an urgent problem needed to be resolved.Firstly, numerical simulation work was carried out for film cooling issues of the subsonic, transonic and supersonic turbine cascade. In the two-dimensional numerical simulation, we studied the impact of film cooling holes, blowing ratio and film hole location on cooling efficiency under subsonic and transonic conditions. Under supersonic conditions, we studied the impact of film hole inclination, blowing ratio, film hole locations, film hole diameter and the Mainstream PRess ratio on cascade’s cooling efficiency. The results showed that, in the subsonic and transonic conditions, film cooling holes’ position and angle have no significant influence on the suction side cascade’s film cooling efficiency. Blowing ratio was the most important factor of affecting the cascade’s cooling efficiency, with the increase of hair cascades ratio, the cooling efficiency was imPRoved, but gradually leveled off after reached a certain value. Under supersonic conditions, blowing ratio is still the most important factor of affecting the cooling efficiency, cooling efficiency, following the change trend of blow ratio, is similar with subsonic conditions. The difference is, in the larger blowing ratio condition, the impact of film hole inclination on the cooling efficiency gradually shows up, different film hole inclinations are quite different in cooling efficiency, the perforMance is the cooling efficiency rises when the angle of incidence increases in the gas film hole downstream.Secondly, numerical methods were applied to study the influence of different film hole shapes, different three-dimensional film hole spacing conditions, different than the Mainstream PRess and different incidence angles on air film cooling effectiveness. The results show that the cooling efficiency of circular hole is lower than square hole, larger aspect ratio square hole has better cooling characteristics. The cooling efficiency of the circular hole outlet downstream decreased rapidly and then leveled off, but when P/D = 2, the cooling efficiency of the square hole outlet downstream decreased more slowly; reducing hole spacing would imPRove the cooling efficiency of film cooling holes downstream; cascade’s cooling efficiency trended down when the Mainstream PRess ratio increased; for different incidence angles of cold air, the circular hole and 2: 1 square hole are similar in variation, which showed that, a sharp decline in the efficiency of film cooling holes downstream, then becomes flat, incidence angle has smaller influence on the cooling efficiency; 3:1 and 4:1 square holes’ sensitivity of the incidence angle of air-conditioning are lower, when the incidence angle changed, the cooling efficiency has no significant variation.