薄滚筒内二元湿颗粒体系混合行为的离散单元模拟研究

采用所建立的四方程线性弹性-阻尼离散单元模型,同时考虑了液桥力的作用,对填充量为40%、含液量为3%的水平薄滚筒内S型(不同直径颗粒)二元湿颗粒体系混合过程进行了数值模拟,并与同等操作条件下不含液的干颗粒体系的混合行为进行了比较,分析了液体对颗粒体系混合行为的影响. 同时还将计算结果与文献中的实验结果进行了比较. 结果表明,由于湿颗粒间液桥力的牵引作用使不同性质的颗粒不易分离,使部分颗粒聚结成团,减弱了离析作用的影响,使得滚筒内湿颗粒的混合程度高于相同条件下的干颗粒体系,且接触力的分布较干颗粒体系更加均匀. 通过对混合过程的模拟,直观地反映了混合过程中颗粒的微观运动特性和内部的力学结构,为研究湿颗粒体系混合过程机理提供了依据和参考. 关键词： 湿颗粒体系 混合 分离 离散单元法

Simulation of mixing process for size-type binary wet particulate systems in a rotating horizontal drum by discrete element method

Using the four-equation of linear spring-dashpot discrete element method and considering effect of the liquid bridge, the mixing and segregation process of size-type binary wet particulate system in a rotating horizontal drum is simulated. The effect of interstitial liquid on the mixing and segregation process is discussed. To assess the accuracy of the simulation result, some comparisons are made with the experimental date in the literature. The simulation results show that the liquid bridge between particles plays an important role in mixing and segregation process, and that the cohesion force induced by liquid-bridge leads to the formation of agglomerates of particles. As a result, segregation may be mitigated and mixing may be enhanced, and the network distribution of the contact forces is more uniform in wet particulate system.