Identification of multiple leaks in pipeline III: Experimental results

Identifying multiple leaks in a water supply pipe is challenging because pipe systems are complex and many parameters need to be estimated. In order to solve this problem, in Part I and Part II of the series of papers Wang and Ghidaoui (2018, 2019), a linearized model of transient wave in pipes was introduced, a maximum likelihood (ML) scheme to estimate leaks was proposed (for large leak number, the iterative beamforming method was used to simplify the ML solution), and the model selection methods were used to decide the leak number. In the present paper (Part III), these methods are experimentally justified via transient tests from a newly-built high-density polyethylene (HDPE) pipe system in the Water Resources Research Laboratory at the Hong Kong University of Science and Technology. Since the experiments are conducted in a viscoelastic pipe, the previous transient wave model (for elastic pipes) is modified to quantify the viscoelastic behavior of pipe wall. Experimental results with two and three leaks show that the proposed approaches are able to accurately localize the multiple leaks and decide the number of leaks.