Suppressing submerged vortices in a closed pump sump: A novel approach using joint anti-vortex devices

The closed sump is a vital inlet structure for low-head tidal pumping stations in coastal regions. The flow instability caused by roof-attached vortices (RAVs) and floor-attached vortices (FAVs) within the sump significantly affects the reliability of the unit operation. Mitigating and eradicating these detrimental vortices is deemed imperative in the realm of engineering applications. Reducing the sources of vortices, improving operating modes, and adding anti-vortex devices (AVDs) are the general ways to suppress the occurrence of vortices. However, few reports exist on the closed pump sumps' joint vortex elimination methods for RAVs and FAVs. Based on a deep understanding of the dynamic evolution behavior of the RAVs and FAVs, a hybrid RANS-LES numerical prediction method is adopted to comprehensively compare the suppression effects of different AVDs on the vortex structure. An effective "elliptical line anti-vortex cone combined with underwater cover plate" joint anti-vortex device (JAVD) is proposed and verified through model experiments. The research results provide analytical ideas for improving the flow field of the pump sump and optimizing hydraulic design.