【摘要】 基于有限元理论建立了变工况环境下排水管道的堵塞检测仿真模型，研究声波在圆柱形管道中的传播特性以及管道内水位变化对声波在管腔中传播模态的影响。分析声波传递过程声波能量的变化并与试验采集的声波信号进行对比，验证声波模态分析模型的准确性，并确定声波对管道内空间结构以及管壁上路径变化处的敏感频段，对带旁支的三通配件的管道模拟管内不同程度堵塞并分析其声波模态的变化规律。结果表明：管道内水位填充率D的上升，增加声波传递过程能量损耗，高阶模态的声波衰减尤为明显且声波出现分裂模态；采用10 kHz以下具有较低频率的正弦变频激励信号能够同时实现管道内空间结构改变(堵塞物)和管壁上路径变化(三通件)处的有效检测，可通过测量声压信号的传递轨迹和幅值变化实现对管道状态的识别，堵塞物相对于管道截面高度的占比、堵塞物数量和位置是影响声波传递特性的主要因素。更多还原

【Abstract】 Based on the finite element theory, a simulation model for blockage detection in drainage pipes under variable working conditions was established to study the propagation characteristics of acoustic waves in cylindrical pipes and the effect of water level change in pipes on the propagation modes of acoustic waves in the pipe lumen. The change of acoustic pressure during acoustic transmission was analyzed and compared with the experimentally collected acoustic signals to verify the accuracy of the acoustic modal analysis model and to determine the sensitive frequency band of acoustic waves to the spatial structure of the pipe and the path change on the pipe wall. On this basis, different degrees of blockage in pipes with tee fittings were simulated and the variation of the acoustic modes was analysed. The results show that: the rise of the filling rate D of the water level in the pipe increases the energy loss in the acoustic transmission process, the acoustic attenuation of higher-order modes is particularly obvious and split modes of the acoustic waves appear; the use of low-frequency sinusoidal frequency excitation signal below 10 kHz can simultaneously achieve the effective detection of changes in the spatial structure of the pipe(blockage) and changes in the path on the pipe wall(tee); the identification of the state of the pipe can be achieved by measuring the acoustic pressure signal transmission trajectory and amplitude changes; the percentage of blockage relative to the height of the pipe cross-section and the number and location of blockages are the main factors affecting the acoustic transmission characteristics.更多还原