【摘要】 采用三维离散元方法,生成不同大小颗粒粒径比与上覆颗粒厚度的颗粒集合体,模拟颗粒振动分离实验。通过离散元数值模拟研究颗粒数目对大颗粒振动分离的影响,揭示水平振动条件下孔隙的产生机制,分析了颗粒振动分离行为的细观机理。研究结果表明:振动分离过程中系统动能沿颗粒集合体高度方向分布不均匀,振动过程中系统下部颗粒所具有的动能更大,系统下部颗粒通过不断碰撞传递能量使得大颗粒底部产生孔隙,小颗粒随后快速填充大颗粒底部孔隙从而将大颗粒位置垫高;在相同粒径比之下,随着颗粒数目的增加,颗粒间碰撞作用和孔隙填充作用更加剧烈,大颗粒完成振动分离所需时间越来越短,但持续增加颗粒数目并不会缩短完成振动分离所需时间。更多还原

【Abstract】 The three-dimensional particle flow discrete element method was employed to study the phenomenon of particle vibration separation. This study aimed to reveal the microscopic mechanism of the interspace that appeared under the condition of horizontal vibration and explore the relationship between the number of particles and the particle vibration separation. The simulated results show that the average kinetic energy between the upper and the lower parts of particles is different. The particles which are on the bottom have higher kinetic energy and will deliver more energy to the large particles to generate an interspace. The particle vibration separation will be completed with the process of interspace filling. In addition,with the increasing numbers of small particles under the same particle diameter ratio,the consumed time for particle vibration separation decreases whereas the average kinetic energy difference increases significantly.However,the continuously increased particle numbers do not shorten the time of separation.更多还原