轴流压气机折线缝式机匣处理扩稳机理

Mechanism of axial-flow compressor stall margin improvement associated with bend skewed slots casing treatment

关键词:  轴流压气机  机匣处理  非定常数值仿真  间隙泄漏流

Key words:  Axial-flow compressor  Casing treatment  Unsteady numerical simulation  Tip leakage flow

摘要:

折线缝式机匣处理能够在改善压气机稳定工作裕度的同时使得压气机的效率得到一定的改善,为揭示折线缝式机匣处理的扩稳机理及其与轴向倾斜缝式机匣处理的差异,对带轴向倾斜缝和折线缝机匣处理的压气机转子内部流动进行了时间精确的全三维数值模拟,数值计算所获得的总性能与试验结果符合良好。详细对比分析了带实壁机匣和处理机匣后压气机转子顶部区域流场结构。更加有效地将顶部间隙泄漏涡轨迹向转子叶片尾缘推移,延迟来流/顶部间隙泄漏流交接面向转子叶片上游运动是折线缝式机匣处理提高压气机失速裕度的机理。

Abstract:

The bend skewed slot casing treatment has the potential to significantly extend the stall margin of the compressor with minimal or no loss in efficiency.In order to uncover the working mechanism by which bend skewed slots casing treatments improve stall margin and also the flow mechanisms the bend skewed slots casing treatments differ from axial skewed slots casing treatment,a time accurate 3-dimentional numerical simulation was performed for the subsonic axial-flow compressor rotor both with bend skewed slot casing treatment and axial skewed slot casing treatment.The numerical results agreed well with experimental data for the global performance.Detailed analyses of the flow visualization at the tip have exposed the different tip flow topologies between the cases with casing treatment and with untreated smooth wall.It was found that the repositioning of the tip vortex trajectory further towards the trailing edge of the blade passage and delaying the movement of incoming/tip clearance flow interface to the leading edge plane are the exact mechanism of stall suppression imposed by bend skewed slot casing treatment