直线振动筛筛面颗粒运动特性分析

Analysis of particle motion characteristics on the screen surface of linear vibrating screen

筛面颗粒运动直接影响筛分设备的筛分效率,为了明确直线振动筛筛面颗粒的运动特性,采用离散元素法(DEM)分析了不同条件下单颗粒在筛面上的运动过程及运动类型,研究了振动方向角、振幅和频率对颗粒运动轨迹、碰撞周期和碰撞间隔的影响。研究结果表明:振幅在10~40 mm范围内,碰撞周期和碰撞间隔随着振幅的增大逐渐增大;频率在3~7 Hz范围内,碰撞周期和碰撞间隔先增大后降低,当频率为6 Hz时,碰撞周期和碰撞间隔最大。振动方向角为20°、30°、50°,70°时,筛面上的颗粒存在滑动运动,振动方向角为80°、90°时,颗粒碰撞周期不发生变化,增大振动方向角会减小颗粒的碰撞间隔。大多数模拟情况下,颗粒在筛面上最初的几次碰撞落点较为密集,筛面开孔时可根据模拟结果和实际生产经验在落点密集的区域增大开孔率。

The movement of particles on the screen surface directly affects the screening efficiency of the screening equipment.The discrete element method(DEM)was used to simulate the particle movement on the screen surface of the linear vibrating screen,the motion process and type of single particles on the sieve surface under different conditions were analyzed.The effects of vibration direction angle,amplitude and frequency on particle motion trajectory,collision period and collision interval were analyzed.The results show that the amplitude is within10~40 mm,and the collision period and collision interval gradually increase with the increase of amplitude.The frequency is within 3~7 Hz,the collision period and collision interval first increase and then decrease,when the frequency is 6 Hz,the collision period and collision interval are the largest.When the vibration direction angle is 20°,30°,50°,70°,the particles on the screen surface slide,and when the vibration direction angle is 80°,90°,the particle collision period does not change,and increasing the vibration direction angle will reduce the collision interval of the particles.In most simulation cases,the particles are densely located in the first few collisions of the sieve surface,the open area can be increased in the area with dense landing points according to the simulation results and actual production experience.