物理学报Issue(15)：1-10,10.DOI:10.7498/aps.64.154501
湿颗粒聚团碰撞解聚过程的离散元法模拟∗
Discrete element simulation of impact disaggregation for wet granule agglomerate
摘要
Abstract
Based on the combination of linear contact model, Coulomb slip contact model and parallel bond contact model, a discret element model (DEM) of wet granule agglomerates with coating structure is constructed. Disaggregation pro-cesses of wet agglomerates in impacting to a horizontal plate are performed by applying particle flow code (PFC). Three failure patterns are obtained corresponding to those in experiment. The variation of velocities and rupture characteristics of liquid bridge in disaggregation process are investigated. Effects of impact velocity, gravity of adhered granules, and rotation of core granule are analyzed. DEM simulations show that there are three disaggregation patterns in the coat-ing structure of agglomerates: impact disaggregation, gravity-impact disaggregation and shear-impact disaggregation, depending on the size of primary particles and the rotation of the core granules. With the enlargement of size, gravity plays an increasingly important role and the impact disaggregation pattern shifts to gravity-impact disaggregation. The rotation of core can generate a shear force to separate the fine and disaggregation pattern to turn to shear-impact disag-gregation. Impacting results in a heterogeneous distribution of granule velocities and a tendency of relative movement in agglomerates. Relative movement will bring about the stretch of liquid bridge between granules. If the maximum separation distance of wet granules exceeds the rupture distance of liquid bridge, disaggregation happens. The ruptures of liquid bridge start from impact point and expand to outward, from bottom to up, from inside to outside in coating agglomeration. It is found that the rupture of liquid bridge needs time for accumulation and goes through three stages termed as slow rupture stage, quick rupture stage and entire rupture stage. With the increase of impact velocity, par-ticle gravity, and rotating speed of core granules, disaggregation processes of wet granule agglomerates become fast and thorough. Impact velocity plays a primary role in disaggregation. DEM simulations are consistent with the experimental results.关键词
湿颗粒/聚团/解聚/离散元法Key words
wet granulation/agglomerates/disaggregation/DEM引用本文复制引用
焦杨,章新喜,孔凡成,刘海顺..湿颗粒聚团碰撞解聚过程的离散元法模拟∗[J].物理学报,2015,(15):1-10,10.基金项目
自然科学基金江苏省基础研究计划(批准号：KB20141124)资助的课题.@@@@* Project supported by the Natural Science Foundation Research of Jiangsu Province, China (Grant No. BK20141124) （批准号：KB20141124）
