气膜孔布局对前缘气膜冷却效率影响的实验

Experimental investigation of film cooling effectiveness on leading edge with various geometries

针对叶片前缘结构的特点，建立了前缘气膜冷却实验台，实验模型由半圆柱面和两个平板组成，在距离滞止线2倍气膜孔直径距离位置布置了1排气膜孔。主流在前缘的湍流度为8％，二次流和主流密度比为1．5，动量比变化范围为0．5～4，分析了在不同动量比下气膜孔间距和径向角变化对径向平均气膜冷却效率的影响。径向角分别为0^o，45^o，65^o，孔间距与孔径的比分别为2，3，4。研究结果表明，随着孔间距的增加，径向平均冷却效率逐渐降低。径向角对径向平均冷却效率的影响非常复杂。

Film cooling effectiveness on leading edge with one row of holes were measured. The model was blunt body with a half cylinder leading edge and two flat plates. One row of holes was located at 2 hole diameters from the stagnation line. Foreign gas injection was used to obtain a density ratio of approximately 1.5. High turbulence intensity was produced by a passive grid. The ratio of hole pitch to hole diameter is 2, 3, 4, respectively. Radial angle is 0^o, 45^o, 65^o, respectively. The effect of hole pitch and radial angles on film cooling effectiveness was studied. The results indicate that film cooling effectiveness decreased with increasing hole pitch on both leading edge and flat plate. Radial angle has sophisticated influence on the film cooling effectiveness. Film cooling effectiveness decreases with increasing radial angle in the case of low momentum flux ratio （ I = 0.5 ） and film cooling effectiveness varies weakly in the case of other momentum flux ratios on the half cylinder leading edge. Film cooling effectiveness decreases with increasing radial angle on the flat plate in the case of all the momentum flux ratios.