Optimal Design Of Mining Roller Screen Based On DEM

Roller screen is a kind of non-vibration,large processing capacity,simple structure screening equipment.It has a wide application prospects in tens of millions of tons of large-scale coal production enterprises.It has important engineering practical significance to optimize the design of roller screen.Therefore,based on DEM(discrete element method),this paper simulates the screening process of roller screen,and the results can provide some reference for the optimal design of roller screen.The main research results are as follows:The DEM simulation of the screening process of roller screen with straight screen surface was carried out.The influence of screening shaft speed,inclination angle of screen surface and adhesion energy density on screening process of spherical and aspherical particles was analyzed.The results show that the influence of screening shaft speed on screening efficiency is slightly greater than that of inclination angle of screen surface,while the influence of screening shaft speed and inclination angle of screen surface on screening speed is not obvious.When screening shaft speed and inclination angle of screen surface are 60 r/min and 6 degrees respectively,the screening effect is the best.The screening efficiency and particle swarm velocity are 94.6% and 1.45 m/s,respectively.Adhesion energy density has no obvious influence on the screening process of spherical particles,but the screening efficiency of aspherical particles decreases with the increase of adhesion energy density.The equal thickness screening of roller screen is realized by using segmented screening surface.The screening process of four groups of roller screen with segmented screening surface is simulated.Compared with the roller screen of straight screening surface under the same conditions.The influence of particle shape,screening shaft speed and adhesion energy density on the screening process of the roller screen with segmented screening surface is explored.The results show that the screening effect is the best when inclination angle of screen surface is 0-3-6-9-12,and screening shaft speed is 60 r/min.Particle shape and adhesion energy density have little effect on screening speed,and the screening efficiency is higher when particle shape is aspherical and adhesion energy density is small.Based on Hertz-Mindlin with Archard Wear model and Relative Wear model,the cumulative contact energy and wear depth of involute disc were studied,and the tangential cumulative contact force and normal cumulative contact force at the top of hobbing were analyzed.The screening process of roller screen with involute,plum and triangular discs and the wear depth at the top of hobbing are compared.The results show that the wear degree of hobbing top is the greatest,and the wear mainly comes from tangential contact force.When involute disc is used,the screening effect is the best,and the wear depth of hobbing top is only 1.94 mm.45 figures,28 tables and 142 references are included in this work.