Abstract: For the difficulties in monitoring and diagnosing the aero-engine liquid fault, this paper divided the liquid fault into early liquid fault and serious liquid fault and analyzed the vibrations features respectively. Firstly, the influence law of unbalanced quantity and early liquid on rotor vibration was studied. Based on the area distribution characteristics of the amplitude-frequency characteristic curve, one identification criterion for early liquid was proposed. Then, the instability vibration characteristics of serious liquid rotor was analyzed. It was found that the instability due to serious liquid occurred, there would be a sudden increase of vibration amplitude and sub-harmonic even beat vibration. Based on the characteristics, three identification criterions for serious liquid were proposed. Finally, a complete monitoring method and diagnostic process of liquid fault was proposed, which could provide early warning before instability and avoid fault from getting worse. 30 sets of experimental data were selected for verification. The results show that the accuracy of the method proposed is 96%, which has engineering application value.

Key words: Aero-engine;Rotor partly filled with liquid;Vibration characteristics;Monitoring method;Identification criteria;Diagnostic process

摘要： 针对航空发动机盘腔积液故障难于监测和诊断的问题，将积液问题分为早期积液和严重积液，分别进行振动特征提取。研究了不平衡量和早期积液对转子振动的影响规律，基于幅频特性曲线区域面积分布特点，提出一个早期积液故障识别准则；分析了严重积液转子失稳振动特征，发现积液转子在发生失稳时会出现振动幅值突增、次谐波分量突增和拍振，基于振动特征提出三个严重积液故障识别准则。结合航空发动机实际工况，提出一套完整的积液故障监测方法和诊断流程，能够实现在转子失稳前发出预警，避免故障升级。通过30组实验数据进行验证，所提出的积液故障识别方法准确率达96%，具备工程应用价值。

关键词: 航空发动机;盘腔积液;振动特征;监测方法;识别准则;诊断流程