凹槽孔槽深和动量比对气膜冷却特性的影响

采用瞬态液晶全表面测量技术测量了凹槽孔的气膜冷却特性,研究了动量比和槽深对冷却效率的影响,并和圆柱形孔的测量结果实施了比较.结果表明:冷气在凹槽内横向传播,凹槽抑制了冷气射流分离,凹槽孔比圆柱形孔提供更多的二维气膜.槽深孔径比为0.75是最佳的.随着动量比的增加,冷却效率值逐渐趋于稳定,冷却效率仅有轻微增加. 

Effect of trench hole depth and momentum flux ratio on film cooling characteristics

Film cooling characteristics of trench hole were measured using a transient liquid crystal full-surface measurement technique.The influence of momentum flux ratio (I=0.5,1,2,4) and trench depth (s=0.5 D,0.75D,D;D stands for film hole diameter) were studied comparison between trench hole and cylindrical hole was conducted.The results show that the trench suppresses coolant jet separation,and the trench hole provides greater lateral film coverage compared with the cylindrical hole.An optimum trench depth is s=0.75 D.With a further increase in momentum flux ratio,the cooling effectiveness levels start to plateau,so increased coolant would not be warranted because only a slight increase in film cooling effectiveness would occur.