Leak Detection in Viscoelastic Pipeline Using Inverse Transient Analysis

Leakage in water transmission systems and distribution networks in addition to waste of water and energy, can cause a declined water quality due to exposure to contaminants at low pressure conditions as well as damages to roads, buildings, and infrastructures. Therefore and due to its negative impacts on economics, environmental, and social safety, determination and control of leakage is one of the most important and complex topics in water supply systems engineering. The current research investigated transient-based techniques for leak detection in Polyethylene water pipe systems. For this purpose, firstly an inverse transient analysis (ITA) tool was developed, and then for testing and validating this model, extensive experiments were carried out at Hydraulic Laboratory of Shahid Chamran University of Ahvaz to collect the necessary data. A selected set of data corresponding to two leak locations with different sizes was used to assess the ITA method. Results indicated that the leak location can be accurately pinpointed using a sample size equal to one period (T=4L/a) of the collected pressure in ITA. The error for estimation of the location for a significant leak was between 0.17% and 2.17% of the pipe length. Also, using two periods (2T) of the pressure signal, the uncertainties in leak quantity estimation were satisfactory, as less than 23% of the real leak quantity. Additionally, the comparison between the observed data and the numerical results in different conditions indicated that the hydraulic model estimated the transient pressure accurately by just incorporating the pipe wall viscoelasticity into the model.