Numerical Simulation Of Flow Field In The Forebay Of Combined Sluice-Pumping Station

As the connecting section of intake channel and intake sump (or suction passage), forebay is an important component part of the pumping station, and it can make flow in the intake channel spread smoothly into the intake sump (or suction passage) and supply a better flow pattern for the pump. The forebay can be divided into the front inflow forebay and the side-direction forebay according to different inflow ways. Flow in the front inflow forebay spreads smoothly and gets a good flow pattern. But side-direction forebay always makes flow in the bad flow pattern, such as circulation, vortex and so on. Therefore, we should avoid using this kind of forebay. But, in actual application, owing to the topography condition, project investment, limit of land use, and sluice-pump station, the side-direction forebay is often adopted. Thus, this will result in disorder of fluid in forebay, uneven distribution of flow speed, partial backflow and whirlpool which affect the efficiency of the pump.Based on Navier-Stokes equations and the standard k-ε turbulent model, this paper took a combined sluice-pump station as an example for research on flow pattern in diffusion channel and suction passage by using FLUENT software. The three dimension entity model of forebay and passage was set up using GAMBIT. And in the process of mesh generation, local refinement was done to improve the quality of the grid. Given reasonable boundary condition, applied SIMPLE algorithm, numerical simulation was obtained. Results show that flow in the forebay appears side-direction. That vortexs exist near not only the wing wall, but also inlet of the suction passage influences hydraulic characteristics of the pump directly. Thus, it’s necessary to put forward some measures to improve the poor flow pattern in the diffusion channel and suction passage.To acquire reasonable flow condition, engineering measures such as changing the wing wall form, extending the sluice pier, adding tri-prisms in the forebay were adopted on the basis of the original design. According to different optimized designs, numerical simulation was done respectively. By comparing the simulation results, an effective design improving the flow pattern in diffusion channel was got in this article finally. The final design changes the side-direction inflow way into the front inflow. Water flows uniformly into the pump and meets the requirements of it.