Experimental and numerical investigations on the effects of leakage on the transient pressures by considering the TVB dynamic friction

Leakage often occurs in the water pipe systems, resulting in water loss, water quality safety and even further structure damage issues. Therefore, the real-time detection and accurate simulation of pipeline leakage is extremely important. However, the previous leakage simulation results often underestimate the transient pressure decay, which could cause the calculation and detection errors. In this paper, an accurate leakage model is developed to predict the transient behavior in a water pipeline with the leakage, in which the effects of the leakage and dynamic friction on the transient pressures are fully considered. The high-efficiency simplified convolutional dynamic friction (Trikha-Vardy-Brown, TVB) is proposed to reflect the effect of dynamic friction. Moreover, a long pipe system with different leakages was designed and conducted to investigate the leakage dynamic behavior and to validate the proposed numerical model in this work. Results demonstrate that the proposed model could accurately reproduce the transient pressure during the water hammer events and the effects of leakage on the transient pressures. Simulation and experimental results show that upstream pressure, leakage number and leakage location directly affect the reflection coefficient, and the amplitude of leakage reflection is proportional to the reflection coefficient. When the upstream pressure is smaller, the leakage and the leakage pressure are larger, and the amplitude of the first peak reflected pressure is larger, while the leakage location mainly affects the fluctuation period of the pressure in the pipe section.