基于互相关分析的前失速先兆检测分析

 针对轴流压气机流动失稳控制中的反馈信号,采用互相关分析方法对前失速先兆信号进行了检测。通过在机匣壁面周向对称布置的动态传感器对压力信号进行检测分析,并在单转子低速轴流压气机上进行了实验研究。实验中分析了不同流量工况时,对称布置动态传感器压力信号互相关系数的变化趋势,并在此基础上对前失速先兆与叶顶间隙泄漏涡非定常性进行了关联性研究;同时也分析了采用叶顶喷气作为控制手段之后,机匣壁面对称布置传感器动态压力信号的互相关系数随着喷气量增加的变化趋势。实验结果表明:互相关检测分析方法能够有效及时地检测到壁面压力锯齿波的破坏程度,有利于提高控制器的响应速度,留给作动机构充足的反应时间。而且叶顶喷气作为控制手段能够提高对称布置传感器动态压力信号的互相关系数,从而实现拓宽稳定裕度的目的。

Detection and Analysis of Early Stall Warning Based on Cross-correlation

Cross-correlation is employed to analyze the pressure time-trace which is detected by the dynamic transducers arranged symmetrically around the casing of an axial compressor, and the experiment is performed in a low speed, single-rotor compressor. The tendency of variation of the cross-correlation coefficients is analyzed with different flow coefficients. The relevance of early stall warning and unsteadiness of tip leakage vortex is also studied, and the early stall warning is associated with the unsteadiness of the tip leakage vortex. When tip air injection is adopted as a control method, the correlation measurements will go up first, and then go down with the increase of the injected mass flow. The experimental results show that the controller can detect the destructiveness of the pressure time-trace earlier with the cross-correlation method, and the actuator can be operated timely to improve the stall margin. The feasibility of tip air injection as a control method is also demonstrated.