外端壁收缩与单向倾斜组合涡轮导叶的三维气动力研究

低展弦比涡轮导叶的外端壁收缩与单向正倾斜组合设计是既可减小两端二次流损失又可以满足冲击冷却叶片叶身需平直要求的技术措施。本文简要阐述了组合设计可减小二次流损失的力学机制、流场特征及三维流场设计分析的评价准则。通过三维流场计算 ,详细分析了诸如单向倾斜角度、子午面外端壁轮廓收缩起点、内外曲率半径等主要特征参数对流场品质的影响。给出了组合设计的方法与步骤及评价流场的定性准则。该组合设计方法对低展弦比高温涡轮导向叶片的成功设计具有指导意义。

Three Dimensional Aerodynamic Investigation of a Turbine Nozzle Guide Vane with Combination Design of Tip Endwall Contouring and Positive Leaned Airfoil

The combination design of tip endwall contouring and positive leaned vane in low aspect ratio turbine nozzle can not only reduce secondary losses on both endwalls,but also match the requirements for using plain blade body when impingement cooling is in use.The paper describes the mechanical mechanism and the flow field character that how the combination design redues the secondary losses.A quality factor which allows qualitative evaluation of the effect of blade design on secondary losses is selected and verified.Based on a lot of 3D computations,the paper investigates in detail the effect of some main characteristic parameters on 3D flowfield,such as leaned angles,the start place of tip endwall contraction and the curvatures of the contours,etc.The design method, steps and the evaluation criteria of flowfield quality have been given.The combination design method has significance for the successful design of a low aspect ratio high temperature turbine nozzle.