一种基于相位度量的低速压气机前失速特征分析方法

Early Stall Characteristics Analysis Method for Low-Speed Compressor Based on Phase Metric

关键词:  航空发动机  轴流压气机  旋转失速  流动失稳  扰动  时延互相关分析

Key words:  Aero engine  Axial compressor  Rotating stall  Flow instability  Disturbance  Time-delay cross-correlation analysis

摘要:

轴流压气机流动失稳现象是制约高性能航空发动机发展的瓶颈问题之一，为了研究前失速流动不稳定性演化特征并探究及时有效的失速预警方法，对低速单转子轴流压气机周向八组静压时序信号进行分析，提出了一种基于相位度量的压气机前失速特征分析方法。首先发展了时延互相关分析方法，精确捕捉传感器信号间的时滞相位差，分析时延处理后对称信号的时延互相关系数变化特征。其次，基于相关系数提出了一种扰动相位度量，获得了扰动的时空演变特征图像，并基于最大扰动相位持续时间分析了前失速阶段时延互相关系数阶段性变化机理和流动不稳定性特征。分析结果表明：与传统互相关分析相比，时延互相关分析有效地消除了周向空间位置差造成的时序信号时间滞后相位差，排除了周向空间位置的非物理干扰，更好地呈现压气机前失速流动状态的微观物理特征。提出的扰动相位度量不仅可挖掘流动失稳存在的阶段性变化特征，还能用于检测压气机周向几何不均匀性。

Abstract:

Flow instability of axial compressor is one of the bottleneck problems that restrict the development of high-performance aero-engines. In order to study the evolution characteristics of early stall flow instability and explore a timely and effective stall warning method， the eight groups of circumferential static time series signals of a low speed isolated-rotor axial compressor were analyzed， and an early stall characteristics analysis method for axial compressor based on phase metric was proposed. Firstly， a time-delay cross-correlation analysis method was developed to accurately capture the time-delay phase difference between adjacent sensor signals， and analyze the variation characteristics of time-delay cross-correlation coefficients between symmetric sensor signals. Additionally， a disturbance phase metric was developed based on the correlation coefficient， by using this metric the temporal and spatial evolution characteristic image of the disturbance was obtained. Based on the maximum phase duration of disturbance， the variation mechanisms of time-delay correlation coefficients and the flow instability characteristics were analyzed in the early stall stage. Study results show that compared to the traditional cross-correlation analysis， the time-delay cross-correlation analysis can eliminate the phase difference and the non-physical interference caused by the circumferential positions of signals， and preferably present the microphysical characteristics of flow during early stall stage. The disturbance phase metric can be used to excavate the variation characteristics of flow instability， and to detect the circumferentially geometric inequality of the compressor.