不同方向的气体管道泄漏声发射信号模态特性分析

Modal characteristics of leakage-induced acoustic emission in different directions of gas pipeline

针对泄漏声发射信号多模态、频散及衰减特性导致泄漏定位误差大的问题,采用导波分析理论和壳体振动理论研究不同方向的泄漏信号的模态特性,通过选取最佳数据采集方向来减少泄漏定位误差。利用壳体振动理论分析管内气体与管壁之间的声学耦合作用,据此选择合适的导波分析模型来研究不同方向的泄漏声发射信号的模态类型、频散及衰减特性。通过实验证实了理论分析,研究结果表明,管道轴向声发射信号的主导模态为纵向模态,且轴向声发射信号表现出最弱的频散和衰减特性,这将为气体管道泄漏声发射信号中单一非频散模态提取提供新的思路。

The problem of large leak location errors induced by multi-modal and dispersive characteristics of gas leakage-induced acoustic emission（AE） is considered. Cylindrical guided wave theory and shell vibration theory are utilized to identify the modal characteristics of leakage-induced signal in different directions of gas pipeline. and the optimal direction of data acquisition is selected to reduce leak location errors. The acoustical coupling between the gas in-pipe and pipe wall is analyzed by using vibration theory of cylindrical elastic thin shell,which is adopted to determine the mode analytical model of guide wave. The mode type,dispersive nature and displacement distribution in different directions of gas pipeline are numerically analyzed by using guided wave theory. Experimental results are the same with the theoretical predictions and demonstrate that the axial AE signal is dominated by a single weakly dispersive longitudinal mode and behaves the weakest attenuation,which can provide new solution for extraction of single non-dispersive mode in gas pipeline.