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为了研究高主流湍流度下大倾斜角异型气膜孔的冷却特性,在主流湍流度为11.82%的流动工况下,采用瞬态液晶传热测量技术对倾斜角均为60°的圆柱孔、水滴孔以及曲面簸箕孔进行了研究。在吹风比为0.5的工况下,3种孔型的气膜贴壁性都较好,上游冷却效率高于下游;在吹风比为1.0的工况下,圆柱孔和水滴孔出现气膜脱离壁面再附着现象,上游冷却效率低于下游;在更大吹风比下,曲面簸箕孔气膜也出现脱离再附着现象。吹风比的增加会显著增强各个气膜孔的对流换热强度,曲面簸箕孔的换热系数比在各个吹风比下都低于圆柱孔和水滴孔,圆柱孔和水滴孔的换热系数比在上游区域较高,而曲面簸箕孔的换热系数比在大吹风比下呈现出先上升后下降的分布特征。实验结果表明,在高主流湍流度条件下,大倾斜角水滴孔和圆柱孔的气膜冷却效果相近,曲面簸箕孔的气膜冷却效果优于这两种孔型。
In order to study the cooling characteristics of large-angled gas film pores under high mainstream turbulence, transient liquid crystal heat transfer measurement was used to analyze the cooling characteristics of gas-hole with large tilt angle of 60 ° at a flow rate of 11.82% Water holes and curved dustpan holes were studied. When the blowing ratio is 0.5, the film adhesion of the three kinds of holes is better and the cooling efficiency of the upstream is higher than that of the downstream. When the blowing ratio is 1.0, the film detachment of the cylindrical hole and the water drop hole Wall reattachment phenomenon, the upstream cooling efficiency is lower than that of the downstream; at larger blowing ratio, the surface dustpan air film also appears detached and then attached. The increase of blowing ratio can significantly increase the convective heat transfer of each film hole. The heat transfer coefficient of the surface dustpan hole is lower than that of the cylindrical hole and water droplet hole at each blowing ratio. The ratio of heat transfer coefficient between cylindrical hole and water droplet hole is The upstream region is higher, while the heat transfer coefficient of curved dustpan hole is higher than that of large blowdown ratio. Experimental results show that under the condition of high mainstream turbulence, the film cooling effect is similar to that of the large-tilt turbulent hole and the cylindrical hole, and the film cooling effect of the curved dustpan hole is better than the two hole types.