融合宽度及位置对叶身/端壁融合叶栅性能影响的数值研究

Investigation on Effects of Width and Position on Performance of Blended Blade and End Wall Cascade

关键词:  扩压叶栅  叶身/端壁融合  角区分离  总压损失  数值模拟

Key words:  Compressor cascade  Blended blade and end wall  Corner flow separation  Total pressure loss  Numerical simulation

摘要:

角区分离是制约压气机负荷提升的关键因素，叶身/端壁融合设计(BBEW)可有效组织角区流动，减弱或消除分离。为了研究融合宽度及其弦向位置两个关键设计参数对性能影响，采用经实验校核的数值方法对所设计原型叶栅及9种叶身/端壁融合叶栅进行研究。结果表明:所设计原型叶栅出口下游截面高损失核心区域的展向位置随攻角增大而逐步抬高；叶身/端壁融合叶栅融合位置位于分离点前、后对性能影响孑然不同:融合位置位于分离点前，叶身/端壁融合叶栅效果随来流攻角增加而逐渐显现，在+10°攻角下最佳融合方案可使14%展高处总压损失减小16.2%；但融合位置位于流动分离起始点之后会在全工况内增大损失。融合宽度则存在最佳值，应小于来流附面层厚度。

Abstract:

Flow separation in corner zone is a key factor to limit the increase of compressor aerodynamic loading. Blended Blade and End Wall Design (BBEW) can efficiently organize the flow status in corner zone and reduce or eliminate the separations. In order to investigate the effects of maximum BBEW width and its position in chord on the performance of cascade，the baseline cascade and nine kinds of BBEW cascades were designed and the numerical simulation method verified by experimental data were carried out. The results show that for baseline cascade，the span wise height of the core position of the high loss zone is raised gradually with the increase of inlet flow incidence angle. The BBEW cascade performance is entirely different when the BBEW chord position is before or after the separation location. If the BBEW chord position is before the separation location，the effect of BBEW designs is more and more with the increase of inlet flow incidence angle. In +10°incidence angle，the best BBEW cascade can reduce the relative total pressure loss 16.2% compared with baseline cascade near the 14% span wise height. But if the chord wise position of the maximum BBEW width is located after the start point of flow separation，the BBEW design will increase the aerodynamic loss in the whole operational scope. There is optimum size for BBEW width. The size of the width should be smaller than the thickness of incoming boundary layer.