不同叶顶结构对燃气透平动叶顶部气膜冷却性能的影响

The Influence of Different Tip Configurations on Film Cooling Performance of Gas Turbine Blade Tip

对不同叶顶结构的GE-E3叶片的气膜冷却现象进行了数值研究,比较了三种不同的叶顶结构:平顶、凹槽顶和平顶开槽孔结构在叶顶部的流动和冷却现象,并分析了吹风比对这三种结构的冷却性能的影响。发现凹槽顶和平顶开槽孔在结构上具有相似性;在叶顶开槽后,既降低了射流动量,又降低了顶端泄漏流速,有助于提高冷却效果,同时由于凹槽顶的槽比开槽孔的槽大,冷却气体和燃气在槽内充分混合,使得凹槽顶结构具有最高的冷却效率值和最低的换热系数值,平顶开槽孔结构次之。

The film cooling phenomenon of flat tip（with or without a trench） and squealer tip on GE-E3 blade was numerically studied.The effect of tip configuration and blowing ratio on the blade tip flow and cooling performance was revealed.It was found that the squealer tip and the flat tip with trenched hole have comparability in configuration： both have a cavity at the end of the film hole.So the coolant momentum and the tip leakage flow velocity in the cavity are decreased,which contributes to the improvement of the cooling effect.Because of the bigger cavity of the squealer tip than that of the flat tip with trenched hole,the cooling air and the leakage flow mix adequately in the cavity,the squealer tip can get the highest cooling effectiveness and the lowest heat transfer coefficient value,and the flat tip with trenched hole follows.And with the increase of the blowing ratio,for all the configurations,the area-averaged cooling effectiveness increases while the area-averaged heat transfer coefficients decreases.