凹坑对并排气膜孔冷却性能的影响研究

Effects of craters on cooling performance of parallel-vented film holes

关键词:  涡轮叶片  气膜冷却  压力敏感漆  冷却效率  凹坑型气膜孔

Key words:  Turbine blades  Air film cooling  Pressure sensitive paint  Cooling efficiency  Cratered film holes

摘要:

为提高燃气轮机热端部件的冷却性能，探索了一种并排气膜孔和波浪形凹坑的组合冷却结构，添加椭圆形凹坑考虑凹坑形状变化的影响。利用压力敏感漆（PSP）技术实验测量了组合结构的冷却性能，结合数值模拟分析了流场结构。在吹风比0.5~2.0内，PSP实验结果显示，并排气膜孔结构产生的气膜冷却效果优于单圆孔结构，布置波浪形凹坑可以显著改善气膜孔下游的流场结构。经过计算，在吹风比为1.0时，波浪形并排凹坑孔对比单圆孔面平均冷却效率提高147.8%，对比椭圆形并排凹坑孔提高46.7%。在四个吹风比下，波浪形并排凹坑孔产生了最佳的气膜冷却效果。

Abstract:

In order to improve the cooling performance of gas turbine hot end components， a combined cooling structure with parallel film holes and wavy craters is explored， with the addition of elliptical craters to account for the effect of crater shape variations. The cooling performance of the combined structure was measured experimentally using the Pressure Sensitive Paint technique and the flow field structure was analyzed by numerical simulation. In the range of blow ratio from 0.5 to 2.0， the results of PSP experiments show that the film cooling performance generated by the parallel film hole structure is larger than that of the cylindrical structure， and the arrangement of wavy crater can significantly improve the flow field structure downstream of the film holes. The calculation shows that， in the blow ratio of 1.0， the average cooling efficiency of the wavy parallel crater holes is improved by 147.8% compared with that of cylindrical structure， and improved by 46.7% compared with that of the elliptical parallel crater. The wavy parallel crater holes produce optimum air film cooling at four blow ratios.