基于LMD谱分析的压气机转静子碰摩故障诊断

摘要

In order to extract fault features of the rotor-to-stator rub-impact for compressor, a method based on local mean decomposition (LMD) spectrum analysis of elastic supporter strain signals was proposed.In this method, the vibrational strain signals of the rotor system during aero-engine operating was obtained by sticking strain gages on the strips of the elastic supporter in the vertical and horizontal directions, the vibrational strain signals were decomposed by LMD method, and the signals obtained by LMD were analyzed through the analysis of cycle frequency spectrum and slice spectrum to extract the characteristics of rotor-to-stator rub-impact fault.The results demonstrate that LMD can effectively decompose the vibration strain signals of elastic supports.Both the cycle frequency spectrum of the first production function (PF) component and the slice spectrum of each PF component for the elastic supporter vibration strain signals can extract rotor-tostator rub-impact fault characteristic frequencies.The validity of the proposed method in the identification and diagnosis of the rotor-to-stator rub-impact fault was verified by the disassembly and inspection results of the impeller blades.%为了提取压气机转静子的碰摩故障特征, 提出一种基于弹性支承振动应变信号的局部均值分解 (LMD) 谱分析方法.该方法通过在转子系统弹性支承垂直和水平方向的弹条上粘贴应变片, 获取转子系统在工作过程中的振动应变信号, 通过对振动应变信号进行LMD分解, 并对LMD分解所得信号进行循环频率谱和切片谱分析, 从而获得碰摩故障特征.分析结果表明:LMD可以对弹性支承振动应变信号进行有效分解;弹性支承振动应变信号经LMD分解得到第1个PF (Production function) 分量的循环频率谱和各PF分量的切片谱均可提取转静子的碰摩故障特征频率.叶轮叶片的分解检查结果验证了该方法对转静子碰摩故障识别与诊断的有效性.