Author(s): Guo Xinlei; Yang Kailin; Wang Tao; Guo Yongxin; Fu Hui
Linked Author(s): Xinlei Guo
Keywords: Leak detection; Hydraulic transient; Pure frequency domain; Unsteady friction; Genetic algorithm
Abstract: A newly developing method called pure frequency domain analysis for leak detection in pipelines is proposed. The method is based on the fact that leaks may directly affect the damping and aberration characteristics of hydraulic transient pressure waveforms in pipeline system, the location and leakage can be determined by analyzing the difference of transient water head response between simulated and measured data in frequency domain. The transient signals are generated by portion sharp closure of a valve from the small constant opening and it needs only few meters of water, the discrete boundary conditions and observation data are both transformed in frequency domain by Laplace transform, the genetic algorithm is integrated into the method to calibrate the location and the quantity of leakage. Some important factors such as wave speed and friction in steady and unsteady state are discussed. The non-linearity errors associated with valve boundary condition can be prevented by consideration of induced flow perturbation curve shape. Examples in physical model tests are studied for demonstration of this method.