高压涡轮变叶顶蜂窝角度二次流动特性研究

Secondary Flow Characteristics of High-Pressure Turbine Variable Angle Honeycomb Tip

关键词:  高压涡轮  复合蜂窝  流动控制  气动损失  叶顶泄漏流

Key words:  High-pressure turbine  Composite honeycomb  Flow control  Aerodynamic loss  Tip leakage flow

摘要:

为减少叶顶泄漏流带来的气动损失，本文对高压涡轮叶顶复合蜂窝的排布角度进行寻优，并分析其气动性能。研究过程保持叶顶蜂窝几何形状不变，改变复合蜂窝在叶顶的排布角度，降低叶顶二次流的总压损失系数和叶顶相对泄漏比。以叶栅出口下游30%轴向弦长位置的面平均总压损失系数为目标参数，利用Isight软件嵌套图形-网格自动生成流程，对0~57°旋转角度内的蜂窝排布方式进行遍历寻优，得到低总压损失的蜂窝排布方式。研究表明，最优排布结果与平叶顶相比，叶栅总压损失降低5.21%，与基准角度蜂窝相比降低1.34%。最优排布方案对叶顶泄漏流的阻碍效果更明显，增大了蜂窝对气流的耗散能力，降低了跨叶顶的横向驱动力，减少了泄漏涡的损失。

Abstract:

In order to reduce the aerodynamic loss caused by tip leakage flow， the arrangement angle of a composite honeycomb at the top of high pressure turbine blade was optimized and the aerodynamic performance at the tip region was analyzed. In the present research， the geometry of the honeycomb at the blade tip was kept unchanged， and the arrangement angle of the composite honeycomb at the blade tip was changed to reduce the total pressure loss coefficient and the relative leakage ratio of the secondary flow at the blade tip. With the plane average total pressure loss coefficient at 30% axial chord length downstream of the cascade outlet as the target parameter， the honeycomb layout mode within the range of 0~57° rotation angle was optimized by using the Isight software nesting graph grid automatic generation process， and the honeycomb layout mode with low total pressure loss was obtained. The results suggested that the optimization honey tip reduced the total pressure loss of the cascade by 5.21% compared with the flat tip and 1.34% compared with the basic honey tip. The optimal arrangement scheme had a more obvious effect on preventing the tip leakage flow， increasing the honeycomb’s ability to dissipate the flow， reducing the transverse driving force across the tip， and reducing the loss of the leakage vortex.