局部阻塞对管道瞬变流频响特性的影响分析及应用

Influence of local blockage on pipe transient frequency response characteristic and its application

为了了解局部阻塞对有压管道系统的影响,采用传递矩阵法分析了局部阻塞对管道瞬变流频响特性的影响及频响图的变化形态与阻塞点位置和阻塞局部阻力系数之间的关系,将其应用于管道局部阻塞的检测,并进行了数值试验验证,结果表明:与正常管道相比,局部阻塞点的存在使管道瞬变流频响图中各次谐波的幅值均不再保持定值,而是随着谐波次数的不同呈周期性变化;奇次谐波的幅值随谐波次数周期性变化的主频率及相位与阻塞点的位置相关,而该主频率对应的幅值与局部阻塞的局部水力损失系数相关,据此可进行管道局部阻塞位置和阻塞程度的检测.因此,基于对管道瞬变流频响特性的分析进行管道局部阻塞的检测是可行的.

Local blockage is a usual fault in pressurized pipe systems. The influence of a local blockage on the frequency response diagram（ FRD） is analyzed and the relationship between the variation pattern of FRD and local the blockage parameters,namely the location and resistance coefficient of the blockage is obtained by using transfer matrix method for a pipe system. Then,based on this relationship,a pipe local blockage detection method is proposed and its feasibility is validated through numerical experiments. The results show that the amplitudes of the even and odd harmonics of a pipe with a local blockage no longer maintain constant compared with a normal pipe,but vary periodically with the harmonic order. The main frequency and phase of the odd harmonics reflect the blockage location,and the amplitude of the main frequency is related to the minor resistance coefficient,consequently based on these facts the blockage location and degree can be detected. The numerical experiments confirm that the pipe local blockage detection is feasible based on FRD analysis.