Numerical simulation was performed to investigate adiabatic film cooling effectiveness of cooling holes over thermal barrier coated superalloy substrate. Divergent, convergent-divergent and curved configuration of cooling holes were compared with the inclined cylindrical hole configuration. The coolant flow was strongly attached with the surface for 35º inclination. The film cooling effectiveness at different blowing ratios of 0.4, 0.8 and 1.2 was analysed. The study was carried out using realizable k-ϵ (RKE) model. The curved hole configuration provided enhanced cooling effectiveness even at 0.8 blowing ratio in comparison with other cases. The presence of curvature reduced the coolant velocity thereby preventing the detachment of jet from the surface and forming a very strong longitudinal film. The coolant jet starts detaching from the surface for blowing ratio higher than 1.2; the high momentum of the film cooling jet causes a lift off the surface. At 1.2 blowing ratio, a greater spread of coolant flow along the test surface was observed. Better film cooling effectiveness was evident at 0.8 and 1.2 blowing ratios. At 0.8, the enhancement in the overall film cooling effectiveness of divergent, convergent-divergent and curved hole configuration was about 14 %, 50 % and 59 %, respectively.

中文翻译：

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TBC涂层涡轮叶片冷却孔构型对薄膜冷却效率影响的数值模拟

进行了数值模拟，以研究热障涂覆的超合金基体上冷却孔的绝热膜冷却效果。比较了冷却孔的发散，收敛发散和弯曲构型与倾斜的圆柱孔构型。冷却剂流牢固地附着在表面上，倾斜角度为35º。分析了在0.4、0.8和1.2的不同吹塑比下的薄膜冷却效率。该研究是使用可实现的k-ϵ（RKE）模型进行的。与其他情况相比，即使在0.8的吹风比下，弯曲的孔结构也可提供增强的冷却效果。曲率的存在降低了冷却剂的速度，从而防止了射流从表面脱离，并形成了非常坚固的纵向薄膜。冷却剂射流开始从表面脱离，吹气比大于1.2；薄膜冷却射流的高动量会引起表面升起。在1.2的吹气比下，观察到冷却剂沿测试表面的扩散更大。在0.8和1.2的吹塑比下，明显的膜冷却效果更好。值为0.8时，发散，收敛发散和弯曲孔构型的总体薄膜冷却效率分别提高了约14％，50％和59％。