来流边界层对压气机平面叶栅角区流动的影响

Effects of Inlet Boundary Layer on Corner Flow in a Linear Compressor Cascade

为更准确地预测压气机静叶角区失速以及为角区流场优化提供理论支持,在压气机平面叶栅环境下,利用数值模拟和实验验证方法,研究来流边界层厚度变化对角区流场及角区失速特性的影响。在角区失速前后的典型工况,利用总压损失系数和折转角的展向分布显示不同流场结构引起的性能变化;利用表面极限流线、总压损失云图和Q判据等手段显示角区涡结构特点。结果表明,当来流边界层厚度从1%展长增加到25%展长时,角区失速提前3°攻角发生,叶栅低损失工作范围缩减近30%。而在角区失速发生后,来流边界层厚度变化对角区失速结构没有明显影响,但仍会增强叶栅内其他区域的二次流效应。

To give a better prediction of compressor stator corner stall and provide theoretical support for corner flow optimization,the numerical simulation and experimental validation are utilized to investigate the effects of inlet boundary layer thickness variation on the corner flow structure and corner stall characteristics of a linear compressor cascade. At the typical conditions before and after corner stall,the spanwise distribution of total pressure loss coefficient and flow turning angle are analyzed to show the performance variation caused by different flow structures. Surface streamlines,total pressure loss coefficient contours and the Q criterion are used to show the feature of corner vortexes. Results show that the corner stall occurred 3° incidence angle ahead by increasing the inlet boundary thickness from 1% span to 25% span,which made the low-loss working range reduced by nearly 30%. After corner stall occurred,the increase of the inlet boundary layer thickness showed no obvious influence on corner stall structure,while it still strengthened the secondary flow effect at other blade passage space.