转筒内D型二元颗粒物料滚落模式的径向分离  

Transverse Separation of D-type Binary Dispersed Granular Materials with Rolling Regime in Cylinder Drum

作　　者：陈辉[1] 赵先琼[1] 刘义伦[1] 肖友刚[2] 刘颖[3] 

机构地区：[1]中南大学高性能复杂制造国家重点实验室,长沙410083 [2]中南大学交通运输工程学院,长沙410083 [3]中南大学建筑与艺术学院,长沙410083

出　　处：《农业机械学报》2015年第6期334-340,共7页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家自然科学基金资助项目(51374241;51275531);湖南省研究生科研创新资助项目(CX2014B059)

摘　　要：针对D型二元颗粒物料在转筒内的分离问题,以粘土颗粒和木制颗粒组成的物料为对象,采用离散单元法模拟了滚落运动模式下物料在转筒内的运动与分离过程。通过颗粒接触数定义物料混合指数,并结合Hong的渗流与凝聚竞争理论定量分析了物料的径向分离。结果表明:滚落运动模式下物料在转筒截面上分为平流层与活动层两部分,颗粒之间的分离运动发生在活动层;颗粒密度差异引起凝聚作用,使木制颗粒向转筒内壁分散而粘土颗粒向中心聚集,物料形成'月亮模式'分离形态;通过配置2种颗粒的半径可引入渗流机理,当渗流作用与凝聚作用相互平衡时,可避免物料发生径向分离;渗流机理的引入不受转筒尺寸的影响。Taking granular materials composed of wood particles and clay particles as sample,the rolling motion and separation of density-type binary dispersed granular materials within a cylinder were simulated by using discrete element method. Mixing index of materials was defined by using contact-number between particles,and then transverse separation process was quantitatively investigated by using Hong＇s theory—the mechanism of competition between percolation and condensation. The results showed that material bed was composed of active layer and passive layer in radial section,where separation between particles was occurred in the active layer. Condensation mechanism,which was caused by density differences between wood particles and clay particles,made the material bed form a moon-pattern separation form. Then wood particles dispersed to the drum wall and clay particles gathered to the center of bed. Percolation mechanism can be introduced by configuring the radios of wood particle and clay particle. The separation could be avoided when percolation effect and condensation effect were balanced each other. The addition of percolation mechanism was not affected by the size of cylinder drum.

关 键 词：转筒 二元颗粒物料 滚落 径向分离 离散单元法 

分 类 号：TQ028.9[化学工程]