声发射衰减特性管道泄漏定位方法

声发射技术具有灵敏度高、实时性强、覆盖范围大等优点.泄漏产生的声发射波沿管壁传播会发生衰减,通过研究衰减系数与金属晶粒散射和热流损失的关系,建立准确的声发射能量衰减模型.在此基础上,针对声发射频带宽的特点对传统衰减定位模型进行改进,提出宽频带声发射源定位模型,该方法先通过实验确定泄漏信号频带,再将滤波后的信号经过小波包...

The pipeline leakage location method based on acoustic emission attenuation characteristics

Acoustic emission (AE) technology has the advantages of high sensitivity, strong real-time and large coverage. The acoustic wave generated by gas pipeline leakage attenuates in the process of propagation. Considering the viscous absorption and heat conduction of medium, the scattering and heat flux loss of metal pipeline, the acoustic wave attenuation model is established theoretically. The accuracy of the attenuation model is verified by fitting the attenuation coefficient through experiments. The traditional attenuation localization model is improved according to the characteristics of acoustic emission wide frequency band, and a wide-band localization model is proposed. Firstly, determine the frequency range of the leakage AE signal. Denoise the signal by Chebyshev band-pass filter, then decompose it by wavelet packet, and the energy each wavelet packet node is used to locate. A three-sensor localization model is proposed for the noise that cannot be completely filtered, which uses three sets of signals to make differences to reduce the influence of noise components. Experiments show that the wide-band localization model is more advantageous than traditional one in short distance transportation. When the leakage rate is 60ml/min, the localization error decreases from 8.90% to 3.43%. After adding a sensor, the error is further reduced to 2.59%, which proves the accuracy of the localization model in this paper.