Analysis And Optimization Of The Inlet Water Flow Pattern Of Dongshengdi Drainage Pumping Station

The forebay and sump are important intake structure for drainage pumping station,and if the inlet flow state is disordered,it will seriously affect the inlet conditions of the pump and reduce the efficiency of the pump.Considering the lateral inlet pumping station,the flow disorder of forebay and sump is complex.Therefore,this paper takes the actual project as the research object,carries out the analysis of the inflow flow state of the double lateral inflow pumping station,and proposes targeted flow state optimization measures.In this paper,taking the Dongshengdi drainage station as the actual background of the project,based on the technique of three-dimensional numerical simulation,the flow state of the forebay and sump of the drainage station under the three operating water level conditions are analyzed.The influence of V-shaped diversion piers and matrix circular columns on the flow state of the forebay during the design and operation of the water level is analyzed,and the effects of the three-stage diversion pier,triangular column and partition on the flow state of the sump are studied.（1）Using large-scale commercial software CFX,numerical simulation of the water inlet building of the Dongshengdi drainage station.Through mesh independence analysis,the total number of computational domain meshes was determined to be 1.86 million.The RNG k-s turbulence model was selected to predict the hydraulic performance of the pumping station under three water level conditions.When there is no rectification measure,under the three water level conditions,the flow state in the forebay is disordered,there is a large area of return flow area,and the main stream of the diversion channel is squeezed,and there is a large-scale deflow area at the side wall of the sump,and the flow rate distribution is extremely uneven.（2）Aiming at the unfavorable flow regimes such as backflow in the forebay,flow regime optimization measures such as straight diversion piers,V-shaped diversion piers,symmetrical river-shaped diversion piers and vertical columns are proposed.Under the designed operating water level condition,the improvement effect of the geometric parameters and position parameters of the V-shaped diversion piers on the flow state of the forebay is studied by means of the orthogonal test.On this basis,the improvement effect of symmetrical river-shaped diversion piers and columns on the flow regime in the pool was further studied.Under this scheme,the flow velocity of the forebay is evenly distributed,the large-scale malignant reflux area disappear,compared with the original scheme,the axial velocity distribution uniformity of the outlet section is increased by 71.51%,the average angle of speed weighting is increased by 45.22°.（3）Aiming at the unfavorable flow state such as backflow existing in the inlet pool,flow state optimization measures such as three-section diversion piers,triangular columns and baffles are proposed.Based on the rectification of the front pool,the improvement effect of the above measures on the flow characteristics of the inlet water in the inlet pool was studied.The deflection area of the side wall of the sump disappears,the water level flows downstream to the horn port,the axial velocity distribution uniformity of the front section of the horn mouth is increased by 19.47%,and the maximum speed weighted average angle is increased by 15.74°.（4）When the minimum operating water level is performed,under the optimal scheme,the return area in the pool disappears completely,the water flow is smooth,the axial velocity distribution uniformity of the front section of the inlet pipe is increased by 23.67%,and the average angle of speed weighting is increased by 12.11°.At the highest operating water level,under the optimal scheme,the water flow in the pool is smooth,the axial velocity distribution uniformity of the front section of the inlet pipe is increased by 35.73%,and the average angle of speed acceleration is increased by 2.73°.This study takes the built pumping station as the object to carry out flow analysis and optimization research,which not only has practical engineering significance,but also can provide reference for other similar pumping stations.