湍流度和吹风比对叶片前缘双出口孔射流冷却效率影响

Influence of turbulence intensity and blowing ratios on cooling effectiveness on leading edge of blade with double-outlet hole injection

为了探讨湍流度对一种新型气膜孔射流气膜冷却影响,利用商业软件提供的有限体积法求解N-S方程,对湍流度分别为0.4%、10%和20%时的双出口孔射流冷却效率进行数值模拟。吹风比变化范围为0.5到2.0。首先将圆柱孔射流冷却效率计算结果和实验数据进行了对比,二者吻合较好。计算得到了双出口孔射流气膜冷却下的流场、径向平均冷却效率。结果表明,湍流度和吹风比对冷却效率都有较大影响。湍流度为0.4%和10%时,最高冷却效率在吹风比1.0时获得;湍流度30%时,最高冷却效率在吹风比2.0时获得。吹风比0.5和1.0时,冷却效率随着湍流度的增加而降低;吹风比2.0时,冷却效率随着湍流度的增加而增加。

In order to investigate the influence of turbulence intensity on the film cooling performance with a novel film cooling hole injection, film cooling effectiveness with double outlet hole injection has been simulated at the turbulence intensity of 0.4%, 10% and 30% by commercial code using the finite volume method. The blowing ratios change from 0.5 to 2.0. The numerical result agrees with the experimental data in the case of the cylindrical hole injection. The flow pathlines and the film cooling effectiveness with the double outlet hole injection have been obtained. The results show that the turbulence intensity and the blowing ratios have significant inluence on the film cooling effectiveness. The optimal blowing ratio is 1.0 when the turbulence intensity is 0.4% and 10%. The optimal blowing ratio is 2.0 when the turbulence intensity is 30 %. At the blowing ratios of 0.5 and 1.0, film cooling effectiveness decreases when the turbulence intensity increases. At the blowing ratio of 2.0, film cooling effectiveness increases when the turbulence intensity increases.