Numerical simulation of rectification measures in outlet sump of pumping station
WANG Yuehua1,2*,WANG Bin1,2,WANG Ziming1,2,ZHOU Shengzhi1,2, YE Long1,2
1. Zhejiang Institute of Hydraulics & Estuary, Hangzhou, Zhejiang 310020, China; 2. Key Laboratory of Estuary and Coast of Zhejiang Province, Hangzhou, Zhejiang 310016, China
Abstract：In order to improve the bad flow pattern in the outlet pool of pump station, the RNG model and VOF method was used to simulate the whole flow field in outlet sump of original design scheme and four modified schemes based on CFD software. The flow pattern, velocity, water level, head loss and head loss coefficient of the outlet sump of the pump station were obtained. The calculation results show that the flow pattern in the outlet sump of the original scheme was disordered and the inflow condition of the tunnel was unstable and the main stream was obviously off the central line. The longitudinal water surface difference is 0.33~0.48 m, and the head loss and head loss coefficient were relatively large. Through the comparison of several schemes, it was recommended to adopt the scheme of circular arc side wall and downward moving tunnel entrance. The four corner side walls of the original scheme were adjusted to circular arcs with radius of 45 m and 36 m, respectively, and the tunnel entrance moves 10 m downstream. The scheme can obviously improve the flow pattern of outlet sump, and the flow can enter the tunnel more evenly. The longitudinal water surface difference decreases the most and is 0.12 m. The uniformity of velocity distribution at the entrance of the tunnel is increased by 10.3%, and the head loss is reduced by 14.7%. According to the recommended scheme, the physical model test results are close to the numerical simulation.
