Hydraulic optimization of a stormwater pumping station by physical and computational fluid dynamics modeling

Hydraulic optimization can enhance the reliability, efficiency, and sustainability of stormwater pumping stations. This study was intended to thoroughly assess the hydraulic performance of a specific stormwater pumping station and to propose improved options for regularizing the flow and minimizing sediment deposition. A 1:5 scale physical model was built and three-dimensional computational fluid dynamics (CFD) models were developed and validated. Response surface methodology (RSM) was employed and integrated with CFD for optimizing the parameters of design modifications, including deflector plates and diversion piers. For the existing configuration, the collecting chamber exhibits a large recirculation zone driven by the oblique approach flow and is prone to sedimentation because bottom shear is insufficient. A properly designed deflector plate can reduce the potential area for sediment deposition by nearly 90%. Flow patterns in the pump sump are primarily governed by the operating scheme and the modeling results demonstrate that significant recirculation and vortices are present. The strategic installation of an additional deflector plate alongside two diversion piers significantly mitigates recirculation and sedimentation risk, with their optimized dimensions and spatial configuration determined through parametric analysis. The CFD framework was coupled with a discrete phase model (DPM) to simulate sediment transport and quantify the self-cleaning benefits of the modifications. Simulations confirm that the optimized configuration increases particle export efficiency across all scenarios, particularly for coarser or denser particles under low-flow conditions, which are traditionally the most problematic for sediment accumulation.