改善局部难冷区域的一种导叶层板端壁

Design of a Vane Laminated End-wall to Reduce Local Regions Difficult to Cool

受二次流的影响,气膜冷却端壁表面存在大量难冷区域。紧凑型层板结构可以实现端壁的双侧冷却,从而缩小难冷面积。本文通过改变气膜孔布局,设计了一种可以有效改善局部难冷区域的层板冷却端壁。在主冷流温比1.5下,测量了端壁表面的温降特性和综合冷却效率分布,通过与均匀气膜布局的层板端壁相比较,发现:采用改进后的层板结构,可以显著降低端壁表面温度,缩小难冷区域面积,获得更均匀的冷却效果。且压力侧根部区域与吸力面前缘区域冷却效果增幅尤甚。另外,此层板的改进优势随着质量流量比的增加变得更明显。

Regions difficult to cool were widely generated at film cooling end-walls by the complex secondary flow.However,compact laminated cooling structure can achieve the two-side cooling effect for vane end-walls to reduce the area of these regions.A new laminated cooling end-wall was designed in this work,through modification of the layout of film-holes,to improve the cooling effect in the regions difficult to cool.The metal temperature variation and overall cooling effectiveness were measured under a mainstream-to-coolant temperature ratio of 1.5.A comparison with the laminated end-wall with uniform axial-layout of film-holes revealed that the modified laminated structure can significantly reduce the area of regions with bad cooling performance,and obtain higher metal temperature reduction and more uniform cooling effectiveness.The most obvious improvements can be observed in the corner of pressure side and leading ledge of suction side.In addition,the benefit of modified layout increased with mass flow ratio(MFR).