Experimental Measurement Of Collision Parameters And Simulation Of Granular Particles

Granular material is one of the most common and most common substances in nature and also has a wide range of applications in engineering.Because of its different shapes,the properties of particles are different.At the same time,due to collision of the particle to particle and the particle to the wall surface,its movement process is far more complicated than the simple fluid motion,especially the interaction between particles and wall are important factors which affect the safety and efficiency of the process engineering equipment.At present there are many experimental studies on particle collisions,most of which are measured by finite instruments with a precision measuring instrument.According to the kinematics principle of particle collision,the passage designs the experimental device which s convenient,simple and efficient and can measure a particle collision.The experiment selects rapeseed particles as experimental subjects,carries out measurement experiment,and take numerical simulation study on the basis of experiment The main research contents are as follows:(1)The basic physical properties of rapeseed particles were measured and analyzed by the related experimental equipment,the results showed that the triaxial size,sphericity,density,moisture content,static friction coefficient with aluminum alloy and the pile angle of rapeseed particles.(2)The collision restitution coefficient of rapeseed and aluminum alloy wall was measured by self-made experimental equipment,and effect of collision recovery factors of the collision incidence angle,the blanking height,the incident speed,the thickness of the collision wall and the roughness of the collision wall on the particle were analyzed.The results show that the impact angle and height have significant influence on the distribution of restitution coefficient.Experimental recovery coefficient is mainly concentrated in the 0.4-0.8.The smaller the collision angle and the larger the height of the material,the more dispersed the restitution coefficient;The influence of wall thickness and roughness on the distribution of restitution coefficient is not obvious.The average normal recovery coefficient decreases with the increase of collision angle,and the average tangential recovery coefficient increases with the increase of collision angle.The average recovery coefficient decreases first and then increases with the increase of collision angle,the minimum value occurs when the angle of incidence is 35 degrees;The average recovery coefficient decreases with the increase of the height and roughness of the material;and the average recovery coefficient increases slightly with the thickness of the wall increases.(3)Based on the discrete element method,collision process between rapeseed granules and aluminum alloy wall was simulated by using EDEM software,and the software analyzes the influence of different particle models on the simulation results,the results show that the small radius of the spherical stacked ellipsoid model simulation results closer to experimental values.The influence of the height of blanking,the roughness of the wall and the angle of incidence on the simulation results are analyzed.Compared with the experimental results,the simulation results are in good agreement with the experimental results,However,the fine morphology of the wall and particle surface was not effectively represented during the simulation.Therefore,there is still a gap between the simulation results and the experimental results.