Numerical Simulation Study On Vibration Characteristics Of Dual-flow Channel Pumping Station Combined With Gate Station

With the need of dual-flow diversion and drainage along the river,dual-flow channel pumping station has been widely used.The problems of natural vibration and unit vibration have a great influence on the stable operation of the whole pumping station.At present,the existing research mainly studies the vibration characteristics of the unit impeller,and further research is needed on the pump station house and its structural vibration.In this paper,based on ANSYS 3D finite element analysis software,the vibration characteristics of gate station and pumping station with dual-flow channel are studied,a series of factors affecting the natural vibration characteristics of station house are studied by modal analysis method,and resonance check is carried out with excitation frequency.The harmonic response analysis method is used to study the dynamic response law of the structure under vibration load and water pressure fluctuation load respectively.The main research contents of this paper are as follows.(1)The natural vibration characteristics of the overall structure of the gate station and the pumping station.Analyzing the influence of different boundary conditions on the natural vibration characteristics of the station building,the results show that the calculation of the natural frequency of the underwater part of the station building should consider the impact of filling soil.The fluid-solid coupling analysis method is used to study the influence of rivers and water bodies on the natural vibration characteristics of the station building.The frequency difference of each order is not more than 5.72%,and the influence of the water body on the natural vibration characteristics of the structure can be ignored.Considering the influence of prestress on the natural vibration characteristics,it is found that the prestress has little influence on the natural vibration frequency of the gate station combined with the pumping station,and the mode diagrams are basically the same.Through the resonance check calculation,it is found that the separation of the natural frequency and the runaway frequency is less than 20%,and the runaway condition should be avoided during the operation of the unit.(2)Dynamic response of structure under unit vibration load.The harmonic response analysis method is used to compare the dynamic response of the structural characteristic parts under different operating conditions.The dynamic displacement,velocity and acceleration response of characteristic parts are mainly studied.Under the same operating conditions and different starting conditions,the amplitude of each direction of unit foundation section under drainage conditions is larger than that under diversion conditions.The best starting condition for diversion is 1#unit starting and 2#unit stopping for standby.(3)Dynamic response of structure under fluctuating pressure load.Construction of fluctuating pressure field by CFD numerical simulation,the harmonic response analysis method is used to fluctuating pressure load in different zones,and at the same time,the vibration load of the unit is superimposed to analyze the response of the maximum dynamic displacement and the maximum dynamic stress at the characteristic part of the station house under different conditions.The research shows that the maximum dynamic displacement of the floor panel of the gate station is 0.34 mm,which is larger than 0.2 mm of the recommended amplitude index.The maximum dynamic stress of each characteristic part of the station building under the three working conditions is low.The maximum total dynamic stress under the drainage condition is larger than that under the diversion condition,and the stress distribution trend and amplitude trend under the drainage condition are the same.