从泄漏声发射产生机理出发，结合壳体振动和导波分析理论构建流体管网泄漏声发射模态分析模型，通过实验修正理论模型并优化数值分析方法，预测不同情况下泄漏声发射模态类型、位移分布、频散曲线及衰减特性。根据模态位移分布提出泄漏多方向声发射数据采集及融合方法，解决泄漏信号因衰减特性导致信噪比低的问题。采用改进的经验小波变换将泄漏多模态声发射信号分解为本征模态集，根据泄漏特征辨识构建本征模态筛选机制，采用改进的归一化Hilbert变换对筛选的本征模态进行时频分析，确定不同模态的到达时间差和对应的频率，结合频散曲线确定频率对应的模态声速，利用两模态到达时间差和模态声速确定泄漏点与传感器之间的距离，结合两传感器之间的距离建立泄漏点方向判定准则，确定两传感器之间和之外的泄漏位置。本课题的研究是对现有流体管网泄漏声发射定位方法的补充和完善，为解决泄漏信号多模态、频散及衰减特性导致定位误差大的问题提供新的思路。

The modal analysis models are developed based on mechanism of leakage-induced acoustic emission (AE) in combination with guide wave theory and vibration theory of cylindrical elastic thin shell, to predict modal types, displacement distribution, dispersive curves and attenuation characteristics of leakage-induced AE in fluid-filled pipe network under different conditions. The leakage-induced multi-directional AE data acquisition and fusion method is proposed according to modal displacement distribution to solve the problem of low signal-to-noise ratio caused by attenuation characteristics of AE. The multi-modal leak AE signals are decomposed into intrinsic mode set by the improved empirical wavelet transform (IEWT). The mechanisms of intrinsic modes selection are established based on leakage characteristics identification. The time-frequency distributions of selected intrinsic modes are obtained by the improved normalized Hilbert transform (INHT) to determine the time difference of arrival (TDOA) of different modes and corresponding modal frequency. The sound velocity of corresponding modes can be obtained by the modal frequency and theoretical prediction of dispersive curves. Hence, the distance between the leakage and sensors can be determined using the TDOA and sound velocity of two modes. Combining the distance between two sensors, the judgment criteria of leakage direction will be built to determine the leakage between and outside the two sensors. The existing leak location schemes in fluid-filled pipe network will be supplemented and perfected through the research in this project, which provides new solution to the problem of large leak location error due to multi-modal, dispersive and attenuation natures of leakage-induced AE signal.