Research Of Bulk Telescopic Chute Dropping Based On EDEM Simulation

Bulk telescopic chute is often used for loading dry bulk cargo at wharf.When conveying fragile materials such as coal and grain,it can slow down the falling materials through the internal buffer structure,so as to prevent material loss caused by excessive drop when throwing materials at high altitude.In the non-working state,the chute reduces its volume by shrinking,which is convenient for avoiding ships and recovering storage.Bulk telescopic chute can effectively reduce material breakage,but there is no mature theory to evaluate its performance in the design process.Because anti-fragmentation and blockage are two opposite contradictions,in order to avoid blockage,the design based on experience is always too conservative.Discrete element method(DEM)is a new numerical simulation method for analyzing and solving dynamic problems of complex discrete systems.Simulation and analysis of particle behavior by establishing solid particle system model,it can solve complex problems in many fields such as bulk material treatment,geomechanics,powder engineering and so on.In this paper,the discharging process of bulk telescopic chute is analyzed based on discrete element theory,and the prediction model of fragmentation and wear is established.The main work is as follows:(1)Taking the discrete element simulation software EDEM as the tool,the coal transportation of bulk material telescopic chute as the research object.Particles and structural parameters were selected according to relevant references.Based on BPM model theory and Hertz-Mindlin with bonding contact model,particle template was designed.Bonding parameters were calibrated by simulating mechanical experiments and impact experiments.Particle breakage and structural wear models were established.The above work lay the foundation for further research work.(2)According to the relationship between flow input and output of chute,the particle flow pattern is divided into dilute flow,dense flow and blockage.The flow characteristics and critical transition of each flow pattern were studied,and the blockage problem of chute was mainly discussed.According to the mapping relationship between structural parameters and particle velocity,a particle velocity calculation model based on structural parameters was established by regression analysis,and the reliability of the calculation model was verified.(3)Particle breakage model and structural wear model are introduced.Reasonable design of simulation scheme.In order to deal with the problem of too long simulation time,SPSS neural network tool is used to expand simulation data and realize the prediction of fragmentation.The results show that the main influencing factors of particle breakage and structural wear are the flow velocity of particle flow and the synergistic effect of other parameters.(4)Using Visual Basic as a platform,the particle velocity calculation model and the predicted results of the neural network are encapsulated.A software for the analysis of bulk material chute is developed.Through this software,the chute designer can obtain the prediction results of material breakage and structural wear during the process of cutting by inputting the initial particle parameters and chute structural parameters,and assist the product design.