均衡运动旋转振动筛DEM数值模拟

DEM numerical simulation on rotary vibrating screen under balanced motion

旋转振动筛广泛应用于各行业对于粉体和胶体的分级。单电机旋振筛的激振力不通过振动体质心,使振动体随质心作圆运动和绕质心作圆锥摆运动。这种运动使得筛面上的垂直振幅不均匀,存在着颗粒物料向筛面周边扩散较快、物料层较厚、筛分效率较低、颗粒均匀度较差的问题。因此提出了一种均衡运动原理的旋振筛,通过DEM数值模拟,从筛分效率的角度直观比较了旋振筛在常规运动和均衡运动下的筛面物料运动规律、颗粒粒度分布情况、固相筛分效率及颗粒运动速度。研究表明:均衡运动下物料向筛面周边旋转扩散更为均匀,其物料层较薄,能有效提高旋振筛的固相筛分效率及筛分颗粒的均匀度,可较好解决颗粒粒径与筛孔孔径比在0.7~1.0之间时颗粒透筛相对困难的问题。

Rotary vibrating screen is widely used in the classification of powders and colloids in various industries.The exciting force of single motor rotary vibrating screen does not pass through the mass center of vibrating body,so that the vibration system moves in a circular motion and a conical pendulum around the center of mass.This kind of movement makes the vertical amplitude on the screen surface uneven,and there are problems such as granular materials diffuse quickly to the periphery of the screen surface,the material layer is thick,the screening efficiency is low,and the particle uniformity is poor.Therefore,a rotary vibrating screen with the principle of balanced motion was proposed.Through DEM numerical simulation,the material movement law on the screen surface,particle size distribution and particle velocity of the rotary vibrating screen under normal motion were intuitively compared with which under balanced motion from the perspective of screening efficiency.The results show that the material rotates and diffuses more evenly around the screen surface under balanced movement,and the material layer is thinner,which can effectively improve the solid-phase screening efficiency of the rotary vibrating screen and the uniformity of the screening particles.It can better solve the relatively difficult problem of particle penetration when the ratio of particle size to sieve aperture is between 0.7 and 1.0.