管道泄漏源定位中最优小波基变换  

Optimal Wavelet Base Transform in Pipeline Leakage Source Location

作　　者：汪建新[1] 王恩浩 WANG Jian-xin;WANG En-hao(School of Mechanical Engineering, Inner Mongolia University of Science & Technology, Baotou 014010, China)

机构地区：[1]内蒙古科技大学机械工程学院,包头014010

出　　处：《科学技术与工程》2022年第12期4797-4803,共7页Science Technology and Engineering

摘　　要：针对压力管道通孔型泄漏源互相关定位的声发射(acoustic emission,AE)信号降噪问题,进行了小波变换系数重构泄漏信号的最优小波基的选取工作。首先分析了管道通孔型泄漏信号的声学特性;然后使用短时傅立叶变换分析了泄漏声发射事件的发生时间,用于获得其在该时间段内的基本时域波形,同时对比基本时域波形与标准小波基的相似性删选出合适的小波基;进一步,通过分析小波变换定位泄漏声发射事件的频率分布确定最优小波基。同时考虑到声速对定位管道泄漏的影响,对管道声速进行现场测量标定。最后以最佳小波基的小波变换系数作为重构信号开展基于互相关的定位实验。实验结果表明,选择横波的波速作为管道检测的声速时,最佳小波基为“morlet”的小波变换系数作为重构信号能够很好地剔除噪声提高管道定位精度。Considering the problem of noise reduction of acoustic emission(AE)signals in the cross-correlation location of through-hole leakage sources in pressure pipelines,the selection of the optimal wavelet base for reconstructing the leakage signal with wavelet coefficient was carried out.Firstly,the acoustic characteristics of the leakage signal of the pipeline through-hole was analyzed.Then,the occurrence time of the leakage acoustic emission event was analyzed by short-time Fourier transform,which was utilized to obtain the basic time-domain waveform in this time period,and the appropriate wavelet base was selected compared with the similarity between the basic time domain waveform and the standard wavelet base.Further,the optimal wavelet basis was determined by analyzing the frequency distribution of leak acoustic emission events located wavelet transform.At the same time,taking into account the effect of sound velocity on the location of pipeline leakage,the sound velocity of the pipeline was measured and calibrated on site.Finally,the wavelet transform coefficients of the optimal wavelet basis was utilized as the reconstructed signal to carry out the positioning experiment based on cross-correlation.Experimental results show that when the wave velocity of the transverse wave is selected as the sound velocity of the pipeline detection,the wavelet transform coefficient with the optimal wavelet base of“morlet”as the reconstructed signal can eliminate the noise and improve the pipeline positioning accuracy.

关 键 词：泄漏 声发射(AE) 小波基 小波变换系数 

分 类 号：TE973.6[石油与天然气工程—石油机械设备]