Analysis Of Sediment Deposition Forms And Control Measures In The Forebay Of Fifth Pump Station In Ningxia

Pump station project is widely applied to agricultural production,flood prevention and urban and rural construction,which plays a pivotal role in national economic construction.Forepond and inlet pool are important parts of pump station project.There are a large number of sand-sand rivers in our country,represented by the Yellow River.The forepond and inlet pond of the pumping station on these silt-laden rivers are prone to sediment deposition.These silting will not only cause the pump station can not operate efficiently and stably,but also bring difficulties to the daily maintenance and management of the pump,and even affect the safe operation of the pump.Based on the solid-liquid two-phase flow theory,this paper uses Fluent fluid calculation software to carry out numerical simulation of the forebay and inlet sump of the pumping station,analyzes the impact of different pump station startup combinations on the flow pattern and sediment deposition of the forebay and inlet sump,summarizes the law of sediment deposition of the pumping station,tries different rectification measures,and finds the best solution to the sediment deposition of the pumping station.The main research contents of this paper include:(1)Based on the RNG k-ε two-equation turbulence model,the numerical simulation of different startup combinations under the clear water condition in the original design scheme of the project is carried out,and the influence of different startup combinations on the flow pattern of the forebay and the inlet pool is analyzed,and the startup combination with relatively good flow pattern in the forebay and the most consistent with the actual engineering condition is obtained for the numerical simulation of sediment deposition under the muddy water condition.(2)Select the Mixture model.Select the combination of symmetrical startup of the unit and the unit at both ends to carry out the numerical simulation of sediment deposition under the muddy water condition of the original design scheme of the project,and summarize the law of sediment deposition in the pump station,that is,sediment deposition always occurs in the vortex with poor flow pattern and slow flow rate,in which the wall vortex near the wing wall on both sides of the forebay,the vortex generated by the pressure of the main flow on both sides of the forebay The vortex generated by the water pump suction in the intake pool is prone to siltation.(3)Select the unit with the largest flow velocity and fully open to study the silt-reducing measures,design different silt-reducing schemes according to the location and cause of sediment deposition,carry out numerical simulation of these silt-reducing schemes,and compare the silt-reducing effects of different schemes.The results show that the combination of splay diversion pier,water pressure plate and separation pier in the forebay,and the change of horizontal straight pipe suction in the original design of the project to elbow suction,the best effect of sediment reduction,and the size and distribution range of sediment volume fraction have been significantly reduced.The research results of this paper will solve the problem of sediment deposition in the actual pumping station project,improve the operating efficiency of the pumping station,and reduce the cost of daily maintenance of the pumping station.It provides a reference for the study of sediment deposition in the forward intake forebay pumping station on the sedimentladen river in the future.