Numerical and experimental investigation on leak discharge-pressure relationship for linear elastic deforming pipes

Abstract

[EN] Large amount of research investigated the flow rate from an individual leak as a function of the internal pressure, but few of them managed to separate the effect of pipe deformation and that of leak hydraulics. In this study, experiments were carried out simultaneously measuring leak area, flow rate and pressure head so that the discharge coefficient can be experimentally determined. The experiments under both free and submerged condition were conducted. A few anomalies were found. For example, the leakage flow rate of submerged discharge was significantly greater than that of free discharge under full turbulence regime. Meanwhile, for submerged discharge, the discharge coefficient was not constant, but increased first and then decreased. Through CFD simulation, this study provided preliminary expansions of the two anomalies. The less leak flow rate of free discharge may be caused by the friction of water flow and air, and the abnormal decrease of the discharge coefficient of submerged discharge may due to cavitation phenomenon. The phenomena observed in this study could offer more information for researchers about leak hydraulics.