摘要
在燃气轮机中,气膜冷却技术能有效地从高温燃气中保护涡轮叶片,如何提高气膜冷却效率是气膜冷却研究的热点问题。使用大涡模拟(LES)模型分析了平板气膜孔在吹风比为0.5工况时气膜孔下游的速度分布,并与实验进行对比验证。在相同吹风比下,通过模拟叶片上不同气膜孔的位置相应的入口速度分布,研究其对气膜冷却效率的影响,以及对气膜冷却过程中占主导地位涡结构的形成和发展的重要影响。随着气膜孔的位置靠后,湍流边界层随之增厚,滚子涡和肾型涡对生成加快,涡强增大,涡核脱离壁面,从而影响气膜冷却效率。湍流边界层的变化对流向和展向的气膜冷却效率和冷却覆盖范围有明显的影响。
In gas turbine, film cooling technology can effectively protect turbine blades from high temperature gas. How to improve the film cooling efficiency is a hot issue in the research of film cooling. The downstream velocity distribution of a flat film-cooling plane when blowing ratio equals 0.5 was analyzed by using Large eddy simulation (LES) model, and compared with experiment. Furthermore, under the same blowing ratio, by simulating the corresponding inlet velocity distribution , the effects of film-cooling hole position on the blade on film cooling efficiency are compared. It's found that the turbulent boundary layer at the inlet have a significant impact on the generation and development of the dominated vortex structures. With the thickening of the turbulent boundary layer, the formation of roller vortex and kidney-type vortex pair is accelerated, the vorticity intensity is increased, and the vortex core is separated from the wall surface, thereby affecting the film cooling efficiency. The change of the turbulent boundary layer has obvious effects on film cooling efficiency and cooling coverage along both of flow direction and span direction.
作者
陈志涯
詹杰民
龚也君
胡文清
CHEN Zhi-ya;ZHAN Jie-min;GONG Ye-jun;HU Wen-qing(Department of Applied Mechanics and Engineering,College of Engineering,Sun Yat-sen University,Guangzhou 510275, China)
出处
《汽轮机技术》
北大核心
2019年第1期29-32,8,共5页
Turbine Technology
基金
中央高校基本科研业务费专项资金资助(No.17lgjc41)
关键词
燃气轮机
气膜冷却
大涡模拟
湍流边界层
gas turbine
film cooling
large eddy simulation
turbulent boundary layer
