某涡喷发动机压气机气动失稳过程的非线性分析

Nonlinear Analysis of the Process of loosing Compressor Aerodynamic Stability in a Turbojet Engine

对某涡喷发动机压气机的气动失稳过程进行了相关积分分析。对节流过程中压气机静压信号进行延时嵌入重构,发现失稳过程中重构相空间的吸引子结构发生了显著变化;应用相关积分值作为压气机内部流动状况变化的评价指标,发现节流过程中压气机第1级端部的流动最先发生不稳定,随后第2级先于第3,4级发生不稳定征兆;1,2级的失速类型为渐进型失速,3,4级为突变型失速;第3级叶根最先发生不稳定,且发展较快,最终导致全叶高失速;低通滤波可以提高相关积分方法检测失速征兆的时效性。分析表明,非线性的相关积分分析方法是进行压气机气动失稳过程研究的有效手段。

The process of loosing compressor aerodynamic stability in a turbojet engine was analyzed using the correlation integral method. Phase space was reconstructed based on compressor static pressure signal during throttling of the engine. Distinct change among attractor structure of the reconstructed phase space was observed and corresponding correlation integral values were calculated to quantify the change of the compressor internal flow. It showed that the tip region of 1st stage lose its stability first,and then 2nd stage,followed by 3rd and 4th stages during throttling. 1st and 2nd stages manifested progressive stall while 3rd and 4th stages manifested abrupt stall. Instability symptom was first detected in the root region of 3rd stage, which developed rapidly and led to full-span stall. Low-pass filtering can improve the effectiveness of correlation integral method in stall precursor detection. Thus, nonlinear correlation integral method is an effective means in the investigation of the process of loosing compressor aerodynamic stability.