利用波形槽改善气膜冷却效率的数值研究

Numerical Investigation on Improving Film Cooling Effectiveness with Wave Shape Slots

为研究具有波形槽结构的冷却孔出口和波形槽扩散角对涡轮叶片气膜冷却效率的影响,设计了3种不同的扩散角波形槽结构,采用数值模拟方法研究了波形槽的下游速度场、温度场及壁面的气膜冷却效率,分析了波形槽及其扩散角对气膜冷却效率的影响。结果表明：在同一吹风比M=1.5时,与标准圆柱孔相比,波形槽结构的展向平均气膜冷却效率提高200%～300%;与横向槽相比,波形槽结构展向平均气膜冷却效率提高60%～120%;小吹风比条件下,3种扩散角波形槽结构的平均气膜冷却效率差别不大,大吹风比条件下,小扩散角波形槽结构具有较高的平均气膜冷却效率。

In order to study the cooling performance of cylindrical holes attached with waveform slots and the influences of the slot diffusion angle on the film cooling effectiveness, three waveform slot structures with different diffusion angles were designed. The flow field, temperature field and the film cooling effectiveness distribution in the downstream of the slots were studied by numerical simulation. Influences of the diffusion angle on the film cooling effectiveness were analyzed. The results showed that： with the same blowing ratio M = 1.5, the spanwise averaged film cooling efficiency of the wave shape slots is improved by 200% - 300% , compared to the standard cylindrical hole, and 60% - 120%, compared to the transverse slot. At small blowing ratio, the difference in the average film cooling efficiency due to the different diffusion angle of the wave shape slot is small, while at high blowing ratio, the average cooling efficiency is higher for the one with small diffusion angle.