Research On Discharging Of High-speed Bucket Elevator Based On DEM-CFD Coupling

With the accelerated pace of modern industrial production,high-speed centrifugal bucket elevator has been widely used in various industries involving bulk cargo handling.At the same time,it is found that the airflow generated by the bucket elevator in the high-speed operation process will affect the trajectory of material and discharge performance.However,most of these studies have neglected the effect of airflow on the material particles,and the results may be deviated from the actual situation.Taking a given type of high-speed centrifugal bucket elevator as the research object,the discharging process under the action of air flow is analyzed by DEM-CFD coupling simulation method in this dissertation.On this basis,the structural improvement scheme of bucket elevator is put forward.The work content enriches the research ideas of bucket elevator,and the research conclusion provides a useful reference for the structural optimization of bucket elevator.The specific work of this paper is summarized as follows:(1)The traditional design method based on continuum mechanics and the discrete element simulation method are used to analyze the discharging process of bucket elevator,and different discharging contour curves under the two methods are obtained.The results show that the discharging contour curve obtained by the traditional design method have a smaller size and can not effectively reduce the collision between the material and the head cover.(2)Establish the three-dimensional fluid calculation domain model of bucket elevator,empolder the UDF dynamic grid program of bucket movement,and simulate the flow field in the body of bucket elevator during discharging process,and obtain the flow field information of bucket elevator under different operating speeds.(3)Establish the drag model of DEM-CFD coupling interface and the coupling simulation model of particle suspension pneumatic conveying,verify the accuracy of the coupling calculation by checking the simulation results by comparing the relevant experimental data in the existing literature;On this basis,the coupling simulation of the discharging process of multi-size materials under multiple operating speeds is completed,and the discharging trajectory,discharging speed,discharging rate and the wear of the head cover under the condition of air flow are obtained.The results are compared with the DEM simulation results under the same parameters.The results show that the airflow inside the body have a certain effect on the discharging process of bucket elevator,and the small particle is most sensitive to the influence of airflow,and the greater the operating speed,the more obvious the reaction is;airflow will reduce the wear of the head cover of bucket elevator to a certain extent.(4)Based on the conclusions of the previous study,the structure of the bucket elevator is improved.The improvement effect is verified by comparing the parameters of flow field results,discharging rate and the wear of the head cover before and after structure improvement by simulation.