An analytical solution for the transients in a pipeline with a variable boundary condition: leak detection in pipe networks using coded transients

Abstract

A time-domain analytical solution for the transients in a pipeline with a small leak has been developed under variable boundary conditions. The solution shows that the presence of a small leak reduces the amplitudes of the resonant frequencies while its influence on the non-resonant frequencies is negligible. The amplitudes of the resonant components are a function of input signal, measurement locations, damping factor of the pipeline and leak size and location. As pipe section in a water distribution network can be considered as a single pipe with two variable boundary conditions at both ends. A new leak detection technique, which is able to detect and locate leaks in pipe networks, has been developed based on the analytical solution. The application of the new leak detection method is similar to the widely used acoustic leak detection techniques involving two monitoring locations across a leak. The new leak detection technique uses fully controlled and purposely generated fluid transient signals - coded transients. Compared to the acoustic based leak detection methods, the proposed method may be applied with a much greater measurement interval and is less influenced by the background noises. Copyright ASCE 2006.