Impinging-film cooling is a kind of hybrid cooling, in which the cooling effectiveness would be influenced by the impingement characteristics. Thus, this paper investigates the effects of impinging parameter variations on the performance of impinging-film cooling. The impinging parameters include jet inclination (30°, 45°, 60°, and 90°), jet-to-slab spacing (1 mm, 1.5 mm, and 2 mm), and jet hole diameter (d = 1 mm, 1.2 mm, and 1.6 mm). In addition, numerical simulation was employed to help in understanding the flow field changes caused by different impinging parameters. The results show that the jet inclination of 90° has higher cooling effectiveness compared to other ones due to the lower turbulent intensities. A smaller jet-to-plate spacing is conducive to the liner cooling attributed to its higher slot velocity. The jet diameter of 1.2 mm shows a great capacity for liner cooling estimated by the cooling effectiveness. An optimal collocation of jet diameter and spanwise hole-to-hole spacing may exist with fixed total jet area according to the cooling effectiveness. The changes of velocity and turbulence intensity distribution due to different impinging parameters account for the difference of cooling effectiveness.

中文翻译：

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冲击参数对冲击膜冷却性能的影响

冲击膜冷却是一种混合冷却，其中冷却效率会受到冲击特性的影响。因此，本文研究了冲击参数变化对冲击膜冷却性能的影响。撞击参数包括射流倾斜度（30°，45°，60°和90°），射流与板坯的间距（1 mm，1.5 mm和2 mm）以及射孔直径（d = 1 mm，1.2毫米和1.6毫米）。另外，采用数值模拟来帮助理解由不同冲击参数引起的流场变化。结果表明，由于较低的湍流强度，与其他喷嘴相比，90°的喷嘴倾斜具有更高的冷却效率。较小的射流到印版间距有利于衬套冷却，这是因为衬套的开槽速度较高。射流直径为1。2毫米显示出很大的衬里冷却能力，这是由冷却效率估算得出的。根据冷却效率，在固定总射流面积的情况下，可能存在射流直径和翼展方向孔与孔间距的最佳搭配。由于不同的撞击参数导致的速度和湍流强度分布的变化，造成了冷却效率的差异。