Numerical risk mitigation and modeling of pump sump system failures

A three-dimensional CFD (Computational Fluid Dynamics) study was performed to evaluate the hydraulic performance of an existing flood‑protection pump sump designed for a discharge of 16.48 m3/s. The study aimed to assess flow uniformity at bell-mouth suction, quantify swirl angles, and identify subsurface vortex formation under operating conditions. A novel trident-shaped splitter combined with dividing walls is proposed to mitigate vortex-induced instabilities. The Reynolds-Averaged Navier–Stokes (RANS) equations combined with the realizable k–ε turbulence model and VOF (Volume of Fluid) approach were solved using STAR-CCM+. Results indicate that vortex intensity and flow separation observed in the original design are significantly reduced with the proposed modifications. Quantitative analysis shows swirl angles below 1.6°, well within Hydraulic Institute limits (5°). Mesh‑independence and pressure‑distribution analysis confirm improved hydraulic stability and reduced risk of mechanical damage.