Abstract In the present work, two different impingement/effusion geometries have been investigated, both having staggered hole configuration and an equal number of impingement and effusion holes. The first geometry, which is designed in case of low coolant availability, has impingement hole pitch-to-diameter ratios of 10.5 in both orthogonal directions, a jet-to-target plate spacing of 6.5 hole diameters, with effusion holes inclined of 20° with respect to the target surface. The second geometry, which is designed in case of high coolant availability, has impingement hole pitch-to-diameter ratios of 3.0, a jet-to-target plate spacing of 2.5 diameters and normal effusion holes. For each geometry, two relative arrangements between the impingement and effusion holes have been investigated, as well as various Reynolds numbers for the sparser geometry. The experimental investigation has been performed by applying a transient technique, using narrow band thermochromic liquid crystals (TLCs) for surface temperature measurement. A CFD analysis has also been performed in order to support interpretation of the results. Results show unique heat transfer patterns for every investigated geometry. Weak jet-jet interactions have been recorded for the sparser array geometry, while intense secondary peaks and a complex heat transfer pattern are observed for the denser one, which is also strongly influenced by the presence and position of effusion holes. For both the geometries, effusion holes increase heat transfer with respect to impingement-only, which can be mainly attributed to a reduction in flow recirculation for the sparser geometry and to the suppression of spent coolant flow for the denser one.

中文翻译：

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在冲击/喷流冷却方案中孔布置对传热作用的实验和数值研究

摘要 在目前的工作中，已经研究了两种不同的冲击/渗出几何形状，它们都具有交错的孔配置和相同数量的冲击和渗出孔。第一种几何形状是在冷却剂可用性较低的情况下设计的，在两个正交方向上的冲击孔间距直径比为 10.5，射流与目标板的间距为 6.5 孔直径，喷液孔倾斜 20°相对于目标表面。第二种几何形状是在高冷却液可用性的情况下设计的，具有 3.0 的冲击孔间距直径比、2.5 直径的射流与目标板间距和正常的喷流孔。对于每个几何形状，已经研究了冲击孔和流出孔之间的两种相对布置，以及稀疏几何形状的各种雷诺数。实验研究是通过应用瞬态技术进行的，使用窄带热致变色液晶 (TLC) 进行表面温度测量。还进行了 CFD 分析以支持对结果的解释。结果显示了每个研究几何形状的独特传热模式。对于较稀疏的阵列几何结构，已记录到较弱的射流相互作用，而对于较密集的阵列，观察到强烈的二次峰和复杂的传热模式，这也受到积液孔的存在和位置的强烈影响。对于这两种几何形状，喷出孔增加了仅与冲击有关的传热，这主要归因于稀疏几何形状的流动再循环减少以及密度较大几何形状的废冷却剂流的抑制。