一种捕捉预示压气机失稳预警信号的新方法的研究

Study of a New Method for Giving Warning Signals of Instability

本文旨在寻求预示压气机失稳发生的预警信号。通过对失稳产生的物理机制的分析可知,压气机系统内脉动压力能量的积累有可能作为失稳先兆的外部表征。据此,本文从能量的角度出发,对多组压气机失稳的实验数据进行了频域,时域分析。结果发现,在压缩系统完全进入失稳以前,动态压力的方差值有一明显的增长过程,而且这一异常现象距失稳有1～2秒的时间间隔,这对实现压气机失稳的在线预报有十分重要意义。

A new method has been developed to give early warning signals just before a compressor runs into instability. Analyses based on prestall pressure signals of several axial compressors reveal that the dynamic pressure energy accumulation in a compressor just before the instability can be used as a precursor signature of the instability. It is illustrated that by using the appropriate RMS of the casing static pressure over the rotor tip an early warning can be obtained about 1-2 seconds before the onset of the instability. This is particularly important because the method is applicable to the spike type stall inceptions as well as the model type ones, the former usually appears abruptly and does not have a precursor.