非轴对称端壁造型对叶片端壁气热性能影响的研究

Research on Effects of Nonaxisymmetric Endwall Contouringon Blade Endwall Aerothermal Performance

关键词:  非轴对称端壁  间隙射流  气膜冷却  气动性能

Key words:  Non-axisymmetric endwall  Purge flow  Film cooling  Aerodynamic performance

摘要:

为了研究非轴对称端壁造型对典型燃气透平叶片端壁气动热力性能的影响，基于双控制型线非轴对称端壁造型方法，建立了间隙射流和主流掺混作用下非轴对称端壁气动热力性能的数值研究模型。在数值验证的基础上，研究了4种不同非轴对称端壁造型几何结构对叶栅端壁流动特性和气膜冷却性能的影响规律。结果表明，针对本文研究的大转折角透平叶片，在叶栅通道前部进行非轴对称端壁造型，会增强端壁的横向二次流，导致叶栅总压损失系数略有增大，会降低端壁的气膜有效度。而在叶栅通道后部进行非轴对称端壁造型，可以有效削弱端壁的横向二次流，减弱通道涡，从而降低叶栅的总压损失系数，同时，能够提升端壁横向平均气膜有效度高达22%，有利于提高端壁的气动热力性能。

Abstract:

In order to study the effect of non-axisymmetric endwall contouring on aerothermal performance of a typical gas turbine blade endwall, the numerical research model was established in consideration of the interaction between purge flow and mainstream flow based on double control curves non-axisymmetric endwall contouring method. Upon numerical validation, the effects of four different non-axisymmetric endwall contouring on blade flow characteristic and endwall film cooling effectiveness were studied in depth. Results indicated that for the gas turbine blade with high turning angle in this study, a non-axisymmetric endwall contouring on the fore part of endwall enhanced the secondary flow strucutres resulting in increase of total pressure loss coefficient, it reduced film cooling effectiveness on the endwall. While, a non-axisymmetric endwall contouring on the rear part of endwall can effectively reduce the endwall transverse secondary flow and passage vortex resulting in reduction of total pressure loss coefficient. It can also improve laterally averaged film effectiveness on the endwall by 22% at most. Hence a non-axisymmetric endwall contouring on the rear part of endwall was benefit for the development of aero-thermal performance of blade endwall.