叶片前缘圆柱形孔和扩张形孔气膜冷却特性研究

采用考虑曲率影响的瞬态液晶测量技术测量了叶片前缘扩张形孔和圆柱形孔的气膜冷却特性,分析了不同孔形在不同平均吹风比下气膜冷却效率的局部分布特征及定量变化关系,结果表明:①与圆柱形孔相比,扩张形孔射流的覆盖面更大,主要覆盖区域的偏移角度更小;②圆柱形孔的平均冷却效率在不同测量区域内均随平均吹风比的增加先升高后下降,扩张形孔的平均冷却效率在孔排间区域随平均吹风比的增加单调升高,在第二排孔后区域各平均吹风比下基本一致;③在实验范围内,扩张形孔的展向平均冷却效率较高.

Experimental research on film cooling characteristics of cylindrical hole and expanding hole on the leading edge

Film cooling characteristics of expanding hole and cylindrical hole on the leading edge were measured using a transient liquid crystal measurement technique considering the influence of curvature.Local distribution characteristics and quantitative relationships of different holes' film cooling effectiveness were analyzed under different average blowing ratios.The results show that:(1) As compared with the cylindrical hole,the expanding hole jet has a larger coverage,the offset angle of the main coverage area is smaller.(2) In different test regions,the average cooling effectiveness of cylindrical hole rises firstly and then decreases with increasing average blowing ratio.In the region between the first and second row of holes,the average cooling effectiveness of expanding hole monotonously increases with average blowing ratio.In the downstream region after the second-row holes,the average cooling effectiveness of expanding hole is basically the same under all average blowing ratios.(3) Within the experimental range,the laterally averaged effectiveness of expanding hole is much larger than that of cylindrical hole.