Transient wave-blockage interaction and extended blockage detection in elastic water pipelines

Abstract

Abstract:Extended partial blockages are common in pressurized water pipelines and can result in the wastage of energy, the reduction in system carrying capacity and the increased potential for contamination. This paper investigates the transient wave-blockage interaction and its application to extended blockage detection in pipelines, where blockage-induced changes to the system resonant frequencies are observed. The frequency shifting is first inspected and explained in this study through wave perturbation analysis, providing a theoretical confirmation for the result that unlike discrete blockages, extended blockages cause resonant frequency shifts in the system. Furthermore, an analytical expression is derived for the relationship between the blockage properties and the resonant frequency shifts and is used to detect the blockages in this study. The obtained results are validated through both numerical applications and laboratory experiments, where the accuracy and efficiency of the developed method for extended blockage detection are tested.

Transient Frequency Responses for Pressurized Water Pipelines Containing Blockages with Linearly Varying Diameters

“…where t = time; x = axial coordinate along the pipeline; A ¼ AðxÞ = pipe cross-sectional area; P = instantaneous pressure in the time domain; and a ¼ aðxÞ = acoustic wave speed, which represents the characteristics of pipe-wall deformation and properties of internal fluid (e.g., water). Note that a frictionless pipeline system with elastic pipe wall is firstly considered in the analytical derivation to highlight the waveblockage interaction (Duan et al 2014). Pipeline systems with linearized steady friction will be further discussed in the numerical applications.…”

“…On the basis of the derived wave-blockage dispersion relationship in Duan et al (2012), a genetic algorithm (GA) based inverse optimization procedure was proposed to determine the physical properties (such as length, size, and location) of potential extended blockages. Duan et al (2014) further inspected the transient wave-blockage interaction and theoretically explained the aforementioned blockageinduced frequency shifts.…”

“…Despite the successful application of this transient-based method for extended blockage detection in many numerical and laboratory tests, blockages used for analysis in previous studies were idealized and simplified to uniform shapes (Duan et al 2012(Duan et al , 2014Lee et al 2013;Meniconi et al 2013;Rubio Scola et al 2017;Tuck et al 2013), which are actually equivalent to multiple pipe sections in series with different diameters connected together. However, real world blockages that are often formed from complex sources and processes are usually in highly random and nonuniform shapes as illustrated in Figs.…”

On the Role of Minor Branches, Energy Dissipation, and Small Defects in the Transient Response of Transmission Mains

“…Within phase #5 ("Experimental data analysis"), the acquired pressure signals are examined to extract all the information (i.e., location, type and severity) about possible defects (e.g., leaks [13], partial blockages [14,15], unwanted partially closed in-line valves [16,17], illegal branches [18], and pipe wall deterioration [6]). A review of the existing techniques for the optimal analysis of the experimental data is beyond the aims of this paper which is focused, as shown below, on the crucial role played by the topology and functioning conditions of the system with respect to transient data analysis.…”

Multiple Leakage Function for a Simple Pipeline System

“…Locating the source of leakage is an important engineering issue for pipeline authorities. There have been many attempts to detect abnormalities in pipeline systems using transient based methods (Duan 2015;Duan et al 2014;Ferrante et al 2014;Haghighi and Ramos 2012;Lee et al 2006;Meniconi et al 2011;Vítkovský et al 2000). Recently, an impedance-based method showed comprehensive calibration (e.g., wave speed, pipeline length, leakage, unsteady friction and valve action) for an experimental reservoir pipeline valve (RPV) system (Kim et al 2014).…”