不同叶顶弯曲对离心叶轮性能影响机理

Influence mechanism of different tip curvatures on the performance of tip-leaned centrifugal impellers

面对现代发动机对离心叶轮性能需求不断提高的背景,叶顶弯曲具备有效改善离心叶轮气动特性的能力,本文通过数值模拟的方式对不同叶顶弯曲方向、弯曲形式、弯曲程度的压气机性能进行预测,基于仿真结果对不同流动状态下压气机内部流场进行分析,给出了叶顶弯曲压气机性能变化机理。结果显示:负弯叶轮有助于提升压气机峰值效率,提高压气机堵塞流量。正弯叶轮则在损失部分效率的情况下,使压气机失速裕度得到提升。弯曲叶轮主要通过改善叶顶前缘载荷,重构叶轮通道内静压分布,从而削弱激波强度、减少二次流损失、抑制低能涡发展,达到提升压气机性能的目的。本文研究结果可为离心压气机叶片改型设计提供参考。

Confronted with the rising demand for enhanced performance in modern engine centrifugal impellers,tip-leaned centrifugal impellers have shown the ability to effectively improve aerodynamic efficiency.This paper utilizes numerical simulations to predict the performance of compressors with varying curvature directions,types,and degrees.Based on these simulations,the flow field within the compressor under different flow conditions is analyzed to understand the performance changes in blade tip-leaned compressors.The results indicate that a negative leaned impeller increases both the peak efficiency and choke flow rate of the compressor.On the contrary,a positive leaned impeller enhances the stall margin,though it sacrifices some efficiency.In tip-leaned impellers,the static pressure distribution within the blade passage is optimized by improving the load at the leading edge of the blade tip.This adjustment weakens shock wave intensity,reduces secondary flow losses,and inhibits the development of low-energy vortices.These findings provide valuable insights for the modification design of centrifugal compressor blades.