高主流湍流度下倾斜角对圆柱孔气膜 冷却特性影响的实验研究
Experimental Research on the Effect of Hole？？Inclined Angle on the Film Cooling Characteristics under High Mainstream Turbulence Intensity

为了研究高湍流度下圆柱孔流向倾斜角对气膜冷却特性的影响,在主流湍流度为11？？82％的工况下,采用瞬态热色液晶测量技术对倾斜角为30°、60°的气膜孔冷却特性进行了研究,并与低湍流度工况下的结果进行对比。实验结果表明:气膜孔倾斜角增大会导致气膜冷却效率下降;主流湍流度增大会提高上游冷却效率,降低下游冷却效率,冷却效率展向分布更加均匀。吹风比的增加导致各倾斜角气膜孔换热系数比显著增加,在小吹风比条件下,换热系数比沿流向时降低,而大吹风比条件下换热系数比呈现先上升后下降的分布;气膜孔倾斜角增大会在整体上强化壁面对流换热强度,主流湍流度增加导致换热系数比明显减小。随着吹风比的增加,下游区域的主流湍流度导致两种倾斜角气膜孔的冷却效率和换热系数比差距增大,在上游区域主流湍流度的影响较为复杂。
To study the influence of inclined angle on the film cooling characteristics under high mainstream turbulence intensity, cylindrical holes with inclined angles 30° and 60° were studied using the transient liquid crystal measurement technique under high mainstream turbulence intensity (11？？82％), and the result was compared with the result under low mainstream turbulence intensity. The results indicate that the film cooling effectiveness decreases with the increase of inclined angle. With the increase of mainstream turbulence intensity, the film cooling effectiveness increases in upstream region and decreases in downstream region, and in addition, the film cooling effectiveness distributes more uniform in the lateral direction. With the increase of blowing ratio, the heat transfer ratio is enhanced obviously for all cylindrical holes. At small blowing ratio, the heat transfer coefficient ratio decreases gradually along the flowing direction. And the heat transfer coefficient ratio has an undulation feature at large blowing ratios. The increase of the inclined angle leads to an enhancement of heat transfer intensity at the same blowing ratio. But the increase of the mainstream turbulence intensity may result in lower heat transfer intensity at the same blowing ratio. With the increase of blowing ratio, the mainstream turbulence intensity？？induced differences of the film cooling parameters between two kinds of inclined？？angle holes grow under two mainstream turbulence intensities in downstream region, while the influence of mainstream turbulence intensity is more complex in upstream region