一种航空发动机压气机喘振检测方法

将发动机压气机出口脉动压力作为喘振检测信号,检验分析了压气机出口脉动压力的统计特征,采用滑动窗口的Johnson转换方法对脉动压力信号进行正态转换,基于统计特征提出了适应发动机任意状态的喘振检测阈值和方法。该方法成功检测出某发动机3次喘振故障,分析得出:发动机压气机出口脉动压力不服从正态分布,稳态过程脉动压力正态转换成功率大于瞬态过程,降低样本容量可有效提高瞬态过程正态转换成功率;对于脉动压力99.95%概率分布的上、下边界距离,其幅值范围在不同转速下差异较大,且随转速增大而增大;根据提出的喘振检测量可设置适应发动机任意状态的固定检测阈值,其检测出发动机喘振及退出喘振所需时间均小于20ms。

A Method for Detecting the Surge of an Aero-Engine Compressor

Taking the fluctuating pressure at the outlet of the engine compressor as a surge detection signal, the statistical characteristics of the fluctuating pressure at the outlet of the compressor being tested and analyzed, and the fluctuating pressure signal being transformed normally by the Johnson transform method of sliding window based on the statistical characteristics, a threshold and a method for surge detection adapted to any state of the engine are proposed respectively. The method is successfully used to detect the surge failures at a certain engine for three times. The analysis shows that the fluctuating pressure at the outlet of the engine compressor does not obey the normal distribution, and the success rate of the normal transformation for the fluctuating pressure in the steady state process is higher than that in the transient process, the sample capacity reduced can effectively increase the success rate of normal transformation in transient process. For the upper and lower boundary distances of the 99.95% probability distribution of the fluctuating pressure, the amplitude range varies greatly at different speeds and increases with the increase of the speed. According to the proposed surge detection amount, a fixed detection threshold can be set adaptable to any state of the engine, and the detection time of starting engine surge and exiting engine surge is less than 20 ms.