Enhancement of vorticity reduction by floor splitter in pump sump to improve pump efficiency

Abstract

The effort to reduce swirls and vortices in pump intake which originated from high vorticity regions in the pumped fluid has been a major task in pump station design because it affects the pump performance and ultimately the energy consumption. In this paper, a numerical study on the influence of cross sectional shape of floor splitter on the effectiveness of vorticity reduction in pump intake was carried out with the aid of computational fluid dynamics (CFD) software. A simulation model setup consisting of a rectangular channel and a column pipe positioned at the downstream of the channel was developed with the incorporation of Reynolds-Averaged Navier–Stokes (RANS) k-∊ turbulence model. The model was tested with the installation of floor splitter at the bottom of the channel directly beneath the column pipe. Four floor splitters with different cross sectional shapes were examined in the simulation. The results showed that the use of floor splitter is effective in reducing flow vorticity. Two of the floor splitter types, which have square and trapezoidal cross sections, produced results similar to the findings in the experiment by Kang et al. (2014) and thus gives some certainties to simulation. Triangular cross section, which was derived from the trapezoidal cross section, exhibited the best overall performance in vortex reduction. On the other hand, another shape derived from the trapezoid, which was a trapezoidal cross section with rounded edges, displayed superior vortex suppression than triangular cross section near pipe entrance but limited to areas without interference from counter flows such as the flow near the back wall. Triangular cross section displayed better performance in the region with counter flows thanks to its sharp apex. These results are helpful to determine our ongoing experimental study as well as actual site installation.