利用横向槽改善气膜冷却效率的数值研究

Numerical investigation on improving film cooling effectiveness with transverse slots

关键词:  簿膜冷却  横向槽+  流动传热  数值计算

Key words:  Film cooling  Transverse slot+  Flow and heat transfer  Numerical calculation

摘要:

为了获得横向槽对气膜冷却效率的影响规律,采用数值模拟方法分别研究了横向槽出口有无斜坡两种冷却结构形式在不同吹风比条件下的流动过程和冷却效率分布情况,并与常规气膜孔冷却结构形式进行了对比,以揭示横向槽对改善气膜冷却效率的机理。研究表明:在横向槽的作用下,射流向主流的垂直扩散受到抑制,二次流在流出横向槽后能更好的贴覆绝热壁面,提高了气膜冷却效率,并且横向槽出口有斜坡的气膜冷却结构在气膜孔中心线上的冷却效率最好。

Abstract:

To investigate the influence of the downstream small coolant jets on film cooling effectiveness,a numerical study of the distributions of the flow fields and cooling effectiveness was employed with different small coolant jets in several ratios.And their distributions were compared with the distributions of the baseline holes to reveal the good effects of the small coolant jets on the film cooling performance.The results show that new weaker counter-rotating vortex pairs(CRVP) generated by the small coolant jets break down the main CRVP strengths,so the film effectiveness is greater with better coverage on the hot side.The centerline adiabatic effectiveness is better at different blowing ratios with the small coolant jets,and the improvement of the laterally averaged adiabatic effectiveness is significant with longer distances between the two small coolant jets.