Abstract Film cooling effectiveness downstream of one row of holes of 30 degree inclination angle was measured by using a steady-state thermochromic liquid crystal technique at blowing ratios of 0.5, 1.0, 1.5 and 2.0, respectively. Three kinds of dual-fanned holes which have the same expanded entrance width and the different expanded exit widths were tested. The configuration of only expanded entrance, but cylindrical exit hole, was tested to examine the effect of the expanded entrance on film cooling performance. The numerical simulation for the three expanded exit configurations was carried out explaining the mechanism of film cooling by the flow and thermal field. The only expanded entrance has a weak influence on film cooling effectiveness. The W o = 1.5 d ${W_o} = 1.5d$ configuration provides a lift of film cooling effectiveness compared to W o = 1.0 d ${W_o} = 1.0d$ configuration. Film cooling effectiveness is not sensitive to the change of configurations from W o = 1.5 d ${W_o} = 1.5d$ to W o = 2.0 d ${W_o} = 2.0d$ . Film cooling effectiveness for W o = 2.5 d ${W_o} = 2.5d$ performs significantly better than the other configurations due to the presence of the anti-vortex. The effect of dual-fanned exit width on film cooling effectiveness is strongly dependent on the blowing ratios.

中文翻译：

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不同出口宽度双扇孔的薄膜冷却效果研究

摘要 采用稳态热致变色液晶技术，在吹气比分别为0.5、1.0、1.5和2.0时，对一排30度倾角孔下游的薄膜冷却效果进行了测量。测试了具有相同扩展入口宽度和不同扩展出口宽度的三种双扇孔。测试仅扩展入口但圆柱形出口孔的配置，以检查扩展入口对薄膜冷却性能的影响。对三种扩展出口配置进行了数值模拟，解释了流场和热场的薄膜冷却机制。唯一扩大的入口对薄膜冷却效果的影响很小。W o = 1.5 d ${W_o} = 1。与 W o = 1.0 d ${W_o} = 1.0d$ 配置相比，5d$ 配置提供了薄膜冷却效率的提升。薄膜冷却效果对配置从 W o = 1.5 d ${W_o} = 1.5d$ 到 W o = 2.0 d ${W_o} = 2.0d$ 的变化不敏感。由于存在反涡流，W o = 2.5 d ${W_o} = 2.5d$ 的薄膜冷却效果明显优于其他配置。双扇形出口宽度对薄膜冷却效率的影响很大程度上取决于吹气比。由于反涡旋的存在，5d$ 的性能明显优于其他配置。双扇形出口宽度对薄膜冷却效率的影响很大程度上取决于吹塑比。由于反涡旋的存在，5d$ 的性能明显优于其他配置。双扇形出口宽度对薄膜冷却效率的影响很大程度上取决于吹塑比。