Dual control technique for mitigating water-hammer phenomenon in pressurized steel-piping systems

Abstract

This paper examined a dual technique -based branching strategy to sustain the conventional technique skills in terms of limitation of wave oscillation period spreading. This technique consists in splitting the single plastic short-penstock used in the conventional one into dual plastic sub-short penstocks placed upstream each of the connections of the original steel piping system to other hydraulic parts. Numerical computations used the method of characteristics for the discretization of unconventional water-hammer model based on the Vitkovsky and the Kelvin-Voigt formulations. The robustness of the transient solver was evaluated by comparing the obtained numerical results with pertinent experimental results. Moreover, the efficiency of the dual technique was explored for a series of operating condition tests including up- and- down surge- initiated water hammer events. Additionally, two plastic material types were utilized for sub- short-penstock pipe-walls, including (HDPE) or (LDPE) plastic materials. Results demonstrated that dual technique is a useful tool to soften both first hydraulic-head peak and crest. Moreover, examination of wave oscillation periods confirmed that the dual technique could markedly improve the efficiency of the conventional one, providing acceptable trade-off between hydraulic-head peaks or crests attenuation, and wave oscillation period spreading limitation. Furthermore, results demonstrated that the amortization of pressure head -rise and -drop was sensitive to the plastic sub- short-penstocks dimensions.