Influence of hydraulic parameter uncertainty on valve-closure water hammer in gravity-driven long-distance water delivery systems

LI Yuqing; ZHANG Jian; YU Xiaodong; CHEN Sheng; QIU Weixin

doi:10.13522/j.cnki.ggps.2025204

Abstract：[Objective]Long-distance gravity-driven water delivery systems are widely used in water transfer and irrigation projects.However,in transient flow calculations,key physical parameters,such as valve characteristics,pipeline roughness,pipeline length,and wave velocity,are often subject to uncertainties,which affect the accuracy of water hammer analysis and the safe operation of pipeline systems.This paper investigates the influence of parameter uncertainty on valve-closure water hammer in such water delivery systems.[Method]The study was based on a combination of theoretical analysis and numerical simulations,through which we systematically evaluated the effects of uncertainties in regulating valve characteristics,pipeline roughness,pipeline length,and wave velocity on water hammer pressure.[Result]①The uncertainty of the parameters characterizing the regulating valve characteristic curve had a significant impact on valve-closure water hammer,with a maximum influence value of up to 3.744.In contrast,the uncertainties of the parameters characterizing pipeline roughness,pipeline length,and wave velocity had relatively minor effects,with their maximum influence values being less than 0.799.②To mitigate the adverse impact caused by uncertainties in the parameters characterizing the regulating valve curve,two engineering measures were proposed:one is to close the butterfly valve before the regulating valve,and the other is to replace the original regulating valve with two regulating valves operating in parallel.[Conclusion]Simulation results indicate that both proposed engineering measures can effectively reduce the maximum water hammer pressure to within the allowable pressure-bearing limit of the pipeline system,thereby reducing the risk of pipe burst accidents and improving the operational safety of long-distance gravity-driven water delivery systems.