Effusion cooling in gas turbine combustors is complicated by swirling flows for anchoring flame, whereas miniature effusion cooling jets are highly directional. This work aims at understanding the directional effects of effusion cooling by studying the effectiveness of cooling film as a function of the offset flow angle β between the main flow and effusion cooling jets. The directional effects of effusion cooling on the cooling film effectiveness are investigated at offset angles of 0, 30, 60, and 90 deg. The cooling film effectiveness is determined by invoking the heat/mass transfer analogy using pressure-sensitive paint that is sensitive to the oxygen partial pressure at the paint surface. Experimental results indicate that offset angles $\beta$ have a strong effect on the cooling film effectiveness. At lower coolant mass flow rates, an offset angle increases the uniformness of the cooling film because the flows from each individual hole coalesce together to form the protective film. At higher coolant mass flow rates, the cooling film effectiveness is less sensitive to the offset angles $\beta$. This is believed to be caused by the coolant flow lifting off the surface and dissipating more easily in the mainstream flow.

燃气轮机燃烧器中的喷流冷却因用于锚定火焰的涡流而变得复杂，而微型喷流冷却射流则是高度定向的。这项工作旨在通过研究冷却膜的有效性作为主流和渗流冷却射流之间的偏移流角 β 的函数来了解渗流冷却的定向影响。在 0、30、60 和 90 度的偏移角下研究了喷流冷却对冷却膜效率的定向影响。冷却膜的有效性是通过使用对涂料表面氧分压敏感的压敏涂料调用传热/传质类比来确定的。实验结果表明，偏角$\beta$对冷却膜效果有很大影响。在较低的冷却剂质量流量下，偏移角会增加冷却膜的均匀性，因为来自每个单独孔的流会聚在一起形成保护膜。在更高的冷却剂质量流量下，冷却膜效率对偏移角不太敏感$\beta$. 这被认为是由于冷却剂流离开表面并在主流流中更容易消散造成的。