基于试验设计的高负荷轴流压气机叶顶喷气参数化研究

Parametric Study of Tip Injection in a High-Loaded Axial Compressor Based on Design of Experiment

关键词:  轴流压气机  叶顶喷气  稳定裕度  叶顶泄漏涡  试验设计  统计学分析 

Key words:  Axial compressor  Tip injection  Stall margin  Tip leakage vortex  Design of experiment  Statistic analysis

摘要:

为了揭示叶顶喷气对压气机稳定裕度的影响规律,对一跨声速轴流压气机进行三维非定常数值模拟,结合试验设计与统计学分析的方法对叶顶喷气展开参数化研究,并分析了叶顶喷气的扩稳机理。研究表明,叶顶喷气整体上提升了压气机的性能,通过激励叶顶环壁附面层抑制叶顶泄漏涡堵塞,达到提升压气机稳定裕度的目的。同时,叶顶喷气会引起压气机失速类型的变化。不同喷气量下的喷气规律是不同的,喷气量与喉部高度、喷气角度间存在交互作用。喷气量较小时应减小喷嘴喉部高度,在相对坐标系下沿转子叶顶前缘中弧线方向喷气；喷气量较大时应增加喉部高度,避免引起叶顶过载失速,喷气应提供正预旋来减小叶顶攻角。喷嘴应与转子叶顶前缘保持一定距离。 

Abstract:

Parametric study of discrete tip injection on stall margin in a transonic compressor was presented with the method of three-dimensional unsteady numerical simulation. Combined with design of experiment and statistic analysis,the law of tip injection on stall margin was achieved and the mechanism of tip injection on enlargement of stall margin was also analyzed. The results show that tip injection is able to improve compressor performance and stability. Tip annulus wall boundary layer is encouraged by tip injection and tip leakage vortex blockage is depressed, which is the main reason of stability improvement. At the same time, tip injection can change the class of tip stall mechanisms in transonic compressor. The law of tip injection on stall margin varies with injection mass flow and there exists interaction between injection mass flow and throat height and between injection mass flow and injection angle. When injection mass flow is relatively less, throat height should be reduced and streamline is supposed to be aligned with rotor blade camber line at the leading edge in the rotating frame of reference. However, throat height should be increased to avoid blade tip stall and positive pre-whirl is suggested to reduce attack angle when injection mass flow is more. A certain distance between nozzle and blade tip leading edge should be kept. 