Assessment of Failure Modes Caused by Water Hammer and Investigation of Convenient Control Measures

Abstract

Economic and efficient transient control measures are always required to ensure safe and performant operation of water distribution networks (WDNs). This study presents extensive numerical investigations of some cost-effective water hammer control strategies in pumping stations. To this end, an abrupt stoppage of pumps was considered for the numerical investigations because this event is likely to generate high transient flow disturbances in WDNs. The transient analysis was conducted using a MATLAB code based on the method of characteristics with linear integration, which is used to discretize the governing momentum and continuity equations. The considered cost-effective water hammer strategies were based on the single and combined usage of flywheels, check valves, and inline valves. Through a detailed numerical study, it was demonstrated that the performance of larger flywheels is relatively limited considering that pumps with higher moments of inertia engender extra costs in terms of space and starting energy. Alternatively, additional water hammer devices should be introduced in the pump station. It was evinced that single usage of check valves guarantees full protection of the pumps; however, it generates an additional severe water hammer effect on the pipeline integrity following the closure. On the contrary, joint use of check valves and an inline valve with an optimized closure rate resulted in a remarkable transient pressure attenuation. Results of this study prove that in some cases, a convenient combination of simple water hammer control devices can alleviate remarkably the transient pressure disturbances in WDNs without the need for more expensive and sophisticated anti-ram devices.