This paper presents a numerical investigation on the concept for improving film cooling performance by placing a ramp upstream the film hole with compound angle. Eight cases with different geometry models are investigated, including the compound angles of 15°, 30°, 45° and the distances between the upstream ramps and film holes (upstream distances) of 5 mm, 10 mm, and 15 mm. The effect of compound angle and upstream distance on film cooling performance is studied. The cases of film cooling on a flat plate, film cooling with compound angle, and film cooling with an upstream ramp are also presented as a contrast. The film cooling performance is evaluated at the density ratio of 0.97 with the blowing ratios ranging from 1.0 to 2.0. Results obtained show that the film cooling performance with compound angle is greatly improved by the upstream ramp, especially in the region downstream the film hole. Both the entrainment of coolant and modified kidney vortices are observed in the case of the novel geometry. The film cooling performance is greatly improved by the dual effect of coolant entrainment and modified kidney vortices. In addition, the film cooling performance is influenced by compound angle and upstream distance. With the increase of compound angle, the lateral adiabatic cooling effectiveness rises. With the increase of the upstream distance, the lateral adiabatic cooling effectiveness goes down.

本文对通过在薄膜孔上游放置一个具有复合角的斜坡来提高薄膜冷却性能的概念进行了数值研究。研究了8个不同几何模型的案例，包括15°、30°、45°的复合角以及5mm、10mm和15mm的上游坡道与膜孔之间的距离（上游距离）。研究了复合角和上游距离对薄膜冷却性能的影响。还对比了平板上的气膜冷却、复合角气膜冷却和上游斜坡气膜冷却的情况。薄膜冷却性能在密度比为 0.97 时评估，吹气比范围为 1.0 至 2.0。获得的结果表明，上游斜坡大大提高了带复合角的气膜冷却性能，尤其是在膜孔下游的区域。在新型几何形状的情况下，可以观察到冷却剂的夹带和修改后的肾脏涡流。通过冷却剂夹带和改良的肾涡流的双重作用，大大提高了薄膜冷却性能。此外，薄膜冷却性能受复合角和上游距离的影响。随着复合角的增加，侧向绝热冷却效率提高。随着上游距离的增加，横向绝热冷却效率下降。薄膜冷却性能受复合角和上游距离的影响。随着复合角的增加，侧向绝热冷却效率提高。随着上游距离的增加，横向绝热冷却效率下降。薄膜冷却性能受复合角和上游距离的影响。随着复合角的增加，侧向绝热冷却效率提高。随着上游距离的增加，横向绝热冷却效率下降。