The flow patterns and sediment deposition in the forebay of a forward-intake pumping station

Abstract

In Northwest China, the concentration of sediment in the Yellow River is high. The flow patterns in the forebay and inlet tank of a pumping station on the river are disordered, and sediment deposition endangers the normal operation and safety of the pumping station. To address this problem, the three-dimensional two-phase water–sediment flow in the forebay of the pumping station is modeled using fluid simulation software, and diagrams of the sediment content and velocity streamline in the flow layers of different sections are obtained. Combined with the multiphase flow theory of mixtures and the realizable k–ε turbulent kinetic energy equation, the location and formation mechanism of each vortex, as well as the area and degree of sediment deposition in the forebay, are analyzed. The actual engineering and numerical simulation results are compared to verify the accuracy of the simulation, and the operating conditions of each pump port under different unit operating conditions are proposed. The results show that the deposition of sediment has different effects on the outlets of the pumps, but its impact on pump Nos. 4, 5, and 6 is small. After desilting, the velocity uniformity and deflection angle of pumps 4, 5, and 6 are improved to a certain extent. This study provides specific guidance for the construction and reconstruction of a pumping station forebay to avoid the impacts of backflow areas and sediment deposition to a certain extent.