Further investigation on water-hammer control inline strategy in water-supply systems

Abstract

This paper revisited the inline re-design strategy used for water-hammer control into an existing steel-piping water supply system to further promote a comprehensive exploration of the entire design driven parameters set, including pressure-head, circumferential-stress and radial-strain behaviors. This strategy consists of replacing a short-section of the transient sensitive region of the original piping system by another made of polymeric pipe-wall material. The 1-D unconventional water-hammer model embedding the Vitkovsky and the Kelvin–Voigt formulations was adopted to describe the flow behavior and solved by the Method of Characteristics (MOC). The model was used to investigate two critical scenarios, including water-hammer up- and down- surge events. The effectiveness of the proposed strategy was evaluated for the high- or low-density polyethylene (HDPE or LDPE) material used for the replaced short-section pipe-wall. Results suggested that the utilized strategy could be successfully employed to amortize pressure-head and circumferential-stress rise and drop. Moreover, the observed amortization rates were found to be strongly dependent upon the short-section material and size. However, two interesting characteristics of the control strategy at hand, not previously reported, also emerged from this study, including the amplification of the radial-strain peaks (and ridges) along with the spread-out of the wave oscillation period.