Leak detection in pipelines by exclusively frequency domain method

A further development of exclusively inverse frequency domain method for leak detection in pipelines is presented and validated. The location and leakage can be determined by analyzing the difference of transient water head response between the 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 a few meters of water. The discrete boundary conditions and observation data are both transformed in frequency domain by Laplace transform. Example in numerical simulation is studied for demonstration of this approach. The application of the method to an experimental pipeline confirms the analysis and illustrates successful detection of the single pipeline leak. The precalibration approach is presented to minimize the effect of data and model error and it splits the method into two parts. One uses data from a known state to fit the parameters of the model and the other uses data from the current state for the fitting of leak parameters using the now calibrated model. Some important practical parameters such as wave speed, friction in steady and unsteady state and the adaptability of the method are discussed. It was found that the nonlinearity errors associated with valve boundary condition could be prevented by consideration of the induced flow perturbation curve shape.