气膜孔形状对排孔下游冷却效率的影响

 实验研究了气膜孔几何形状及吹风比对孔排下游的局部冷却效率的影响。所用孔形是簸箕形孔、圆锥形孔及圆柱形孔,实验的参数范围为二次流孔径雷诺数 Re=10000～ 25000,二次流吹风比 M=0.3～ 2.0,在上述范围选取了 26个工况分别对 3种孔形进行了实验。结果表明 :圆锥形孔、簸箕形孔及圆柱形孔的最佳吹风比分别为 1.0,0.7及 0.5。当吹风比大于 0.7时,带有扩张型出口的气膜孔的冷却效率和冷却区域均优于圆柱形孔。

EFFECTS OF HOLE SHAPE ON FILM COOLING EFFECTIVENESS

Effects of hole shapes on film cooling effectiveness downstream of film cooling holes were investigated. Experiments on dust pan shaped holes, cone shaped holes and round holes have been conducted with secondary flow Reynolds number ranging from 10,000 to 25,000 and blowing ratio ranging from 0.3 to 2.0. Measurements are taken for 26 conditions. Results show that the optimal blowing ratio is 1.0 for the cone shaped holes, 0.7 for the dust pan shaped holes and 0.5 for the round holes. The film cooling effectiveness and cooled area of dust pan shaped holes and cone shaped holes are evidently superior to those of round holes in cases of blowing ratios greater than 0.7.