气体管道泄漏声发射单一非频散模态定位

Leak location in gas pipelines by extraction of single non-dispersive mode from leakage-induced acoustic emission signal

针对气体管道泄漏声发射信号的多模态、频散特性导致互相关泄漏定位误差大的问题,提出采用单一非频散模态提取的气体管道泄漏声发射定位方法。对检测信号的互谱加窗,并根据模态波数确定窗参数,可获得泄漏声发射信号的单一非频散模态导波的互谱。对单一非频散模态导波的互谱进行傅里叶反变换,得到泄漏声发射中单一非频散模态信号的互相关函数以及时延估计,就可以采用单一非频散模态声速,更准确计算出泄漏位置。对气体管道泄漏进行定位实验,相比用未经分解的泄漏声发射信号进行定位,由于声发射单一非频散模态信号的相关性增强,且选用的声速更准确,定位相对误差平均降低7%以上。这表明,通过提取泄漏信号互谱的单一非频散模态成分进行时延估计,可以提高泄漏检测的有效性和减小定位误差。

The correlation-based leak location errors are large due to the multi-modal and dispersive characteristics of leakage-induced acoustic emission. One kind of leak location in the gas pipelines by extracting the single non-dispersive mode is proposed in this study.The cross-power spectrum of the single modal and non-dispersive component in the leak acoustic emission can be obtained by applying the weighing window with parameters of the wave number of the relative mode. Then,the cross-power spectrum of a single modal and non-dispersive component is analyzed by the inverse Fourier-transformed to acquire the cross-correlation for estimating the time delay.Hence,the acoustic velocity of a single modal and non-dispersive component can be used for calculating the leak position more accurately. The experiments of leak location indicate that the relative error is reduced at least 7%. The reason is the enhancement of correlativity of a single modal and non-dispersive component in leak acoustic emission and the adoption of a more accurate acoustic velocity. It shows that the time-delay estimation by extracting the single-modal and non-dispersive component in the cross-power spectrum of leakage-induced acoustic emission signals will enhance the leak detection and location.