基于平行压电阵列的阀门泄漏声发射源定位方法

Acoustic Emission Source Localization Method for Valve Leakage Based on Parallel Piezoelectric Array

针对阀门泄漏故障的问题,提出了基于平行压电阵列的阀门泄漏声发射源定位方法.针对阀门曲面结构的特点,在阀体底部布置了两条平行线性传感器阵列.首先,利用平行压电阵列采集阀门泄漏时产生的声发射信号;其次,计算各自阵列协方差及其特征值,通过比较特征值的大小,确定声发射信号源的大致区域,再利用近场多重信号分类算法进行空间谱估计,在子阵列上建立局部坐标,得到与声发射源对应参考阵元的极坐标,即距离和角度;最后,通过坐标变换,将局部坐标轴中的极坐标转换到整体坐标中.通过DN50的闸阀进行了试验,试验结果表明:该方法可以有效地对阀门声发射源进行定位,减小了阀门泄漏故障的误判,可为阀门故障预测提供参考知识.

To solve the problem of valve leakage fault, parallel piezoelectric array based method is proposed for locating acoustic emission source caused by valve leakage. According to the surface characteristics of valve structure, two parallel linear sensor arrays are arranged at the bottom, and each sensor array contains 2M PZT. Firstly, parallel piezoelectric array is used to collect the acoustic emission signal when the valve leaks. Secondly, the covariance of each array was calculated and corresponding eigenvalues were decomposed, and hence the approximate area of acoustic emission signal source was determined by comparing their eigenvalues. In addition, results by spatial spectral estimation using the near-field multiple signal classification algorithm were obtained and the peak of spatial spectral was assumed to be related with the acoustic emission source coordinate. Finally, the polar coordinates in the local coordinate axis were transformed into the global coordinate. The experimental results of DN50 gate valve show that this method can locate the valve acoustic emission source accurately, which can reduce the misjudgment of valve leakage failure, and provide guidance for the prediction of valve failure.