Flow Characteristics and Anti-Vortex in a Pump Station with Laterally Asymmetric Inflow

Abstract

In a laterally asymmetric intake pumping station, the flow direction in the forebay is not consistent with flow in the intake channel. Thus, the adverse flow patterns, such as bias flow, large-scale vortex and asymmetric flow occur frequently in the forebay and sump. Based on the Reynolds-averaged Navier-Stokes (RANS) equation and the RNG k-ε turbulence model, a recent flow pattern in a laterally asymmetric intake pumping station was numerically simulated and analyzed, and effective vortex elimination measures were proposed. For the original scheme, seriously biased flow combined with large-scale vortices were observed in the forebay and several vortices occurred in the sump. To suppress the clash inflow in the south and north intake channel, the “straight diversion pier + curved wing wall” and “straight diversion pier + curved wing wall + V-shaped diversion pier” were installed separately. The” symmetrical 川-shaped diversion pier” and “symmetrical 川-shaped diversion pier + circular column” was utilized to eliminate the bias flow and large-scale vortices in the forebay. Finally, the “three- sectional diversion pier”, “three- sectional diversion pier + triangle column” and “three- sectional diversion pier + triangle column + straight back baffle” was applied to decrease the vortex and asymmetric flow near the suction pipe of the sump. By attaching the rectification measure schemes in the intake channel and the forebay, the bias flow and large-scale vortex in the forebay were suppressed to varying degrees. The schemes significantly reduced the recirculation coefficient and greatly reduced the recirculation volume. By utilizing the vortex elimination measures in the sump, the vortex and asymmetric flow basically disappeared, the velocity distribution tended to become more uniform, and the flow rate distinction of each pump was smaller. The outcome can be used to provide a reference and basis for the improvement of flow pattern in similar laterally asymmetric intake pump stations.