Experimental Evidence of Leaks in Elastic Pipes

Abstract

Several studies have been carried out in recent decades to establish a relationship between total head and leaks. In literature, the leakage governing equations have been analysed in light of pipe materials, water head, leak dimension or shape. Most of these contributions questioned the classical Torricelli equation, demonstrating through experimental evidence that the classical orifice law can give unsatisfactory results. Nevertheless, starting from the Torricelli equation, other exponential or linear governing equations have been proposed as mathematical models able to reproduce the leakages in water distribution systems (WDSs). To investigate the validity of the proposed governing equations, an experimental campaign was carried out by means of a water distribution network composed of approximately 500 m of polyethylene pipes. The experiments were designed to investigate the effects of leak area and pipe rigidity on discharge. Furthermore, the effect of leak size enlargement with water head was analysed. Finally, the proposed research contributes to the population of a database for estimating the coefficients of head-discharge relationships.

Impact of Main Pipe Flow Velocity on Leakage and Intrusion Flow: An Experimental Study

“…Early studies have shown that the flow through a leak opening is related to the pressure raised to an exponent that varies typically from 0.5 to 2.5 depending on: the material of the pipe, the shape of the leak and the system pressure [6]. Recent studies by many researchers on various pipe materials and leak configurations support the observation under both leakage [7][8][9][10][11][12][13][14][15] and intrusion [5,16]. Regarding the amendment to the equation, the effects of orifice shape and size on the orifice discharge coefficient has been investigated [17,18].…”

Energy Saving in Water Distribution Network through Pump as Turbine Generators: Economic and Environmental Analysis

“…It is known that even though several efforts have been made to reduce hydraulic leakages in WDN, almost all the networks are characterized by water losses. The leakages are strictly connected with the pressure in the networks (see De Marchis et al [39]) thus the use of PATs, able to produce renewable energy reducing the pressure, represent a double environmental challenge, worthy of extensive future investigations.…”

Incorporating the Modified Orifice Equation into Pipe Network Solvers for More Realistic Leakage Modeling

“…Several causes for the power leakage exponent diverging from the theoretical value of 0.5 have been investigated, including leakage hydraulics (Van Zyl & Clayton, 2007), soil-leak interaction (Walski, 2006;Van Zyl et al, 2013) and the distribution of leaks in a network (Schwaller & Van Zyl, 2014). However, the overriding cause of variations in the leakage exponent has been shown to be that leak areas are not fixed, but vary with system pressure (May, 1994, Van Zyl & Clayton, 2007Cassa et al, 2010;Ferrante, et al, 2011;Massari et al, 2012;De Marchis et al, 2016;Fox et al, 2016). In addition, the variations in leak area have been shown to be a linear function of pressure head under both elastic and viscoelastic deformation conditions for different leak types, pipe materials and loading states (Cassa & Van Zyl, 2013;Van Zyl & Cassa, 2014;Malde, 2015;Ssozi et al, 2016).…”