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A fast adhesive discrete element method for random packings of fine particles
Chemical Engineering Science ( IF 4.7 ) Pub Date : 2019-01-01 , DOI: 10.1016/j.ces.2018.09.026
Sheng Chen , Wenwei Liu , Shuiqing Li

Abstract Introducing a reduced particle stiffness in discrete element method (DEM) allows for bigger time steps and therefore fewer total iterations in a simulation. Although this approach works well for dry non-adhesive particles, it has been shown that for fine particles with adhesion, system behaviors are drastically sensitive to the particle stiffness. Besides, a simple and applicable principle to set the parameters in adhesive DEM is also lacking. To solve these two problems, we first propose a fast DEM based on scaling laws to reduce particle Young’s modulus, surface energy and to modify rolling and sliding resistances simultaneously in the framework of Johnson-Kendall-Roberts (JKR)-based contact theory. A novel inversion method is then presented to help users to quickly determine the damping coefficient, particle stiffness and surface energy to reproduce a prescribed experimental result. After validating this inversion method, we apply the fast adhesive DEM to packing problems of microparticles. Measures of packing fraction, averaged coordination number and distributions of local packing fraction and contact number of each particle are in good agreement with results simulated using original value of particle properties. The new method should be helpful to accelerate DEM simulations for systems associated with aggregates or agglomerates.

中文翻译:

一种用于细颗粒随机堆积的快速粘合离散元方法

摘要 在离散元法 (DEM) 中引入降低的粒子刚度允许更大的时间步长,从而减少模拟中的总迭代次数。尽管这种方法适用于干燥的非粘性颗粒,但已经表明,对于具有粘性的细颗粒,系统行为对颗粒刚度非常敏感。此外,还缺乏一个简单适用的设置粘合剂DEM参数的原则。为了解决这两个问题,我们首先提出了一种基于缩放定律的快速 DEM,以在基于 Johnson-Kendall-Roberts (JKR) 的接触理论框架内降低粒子杨氏模量、表面能并同时修改滚动和滑动阻力。然后提出了一种新颖的反演方法来帮助用户快速确定阻尼系数,粒子刚度和表面能重现规定的实验结果。在验证了这种反演方法之后,我们将快速粘附 DEM 应用于微粒的堆积问题。每个颗粒的堆积率、平均配位数和局部堆积率分布和接触数的测量与使用颗粒特性原始值模拟的结果非常吻合。新方法应该有助于加速与聚集体或附聚物相关的系统的 DEM 模拟。每个粒子的平均配位数和局部堆积分数分布和接触数与使用粒子特性原始值模拟的结果非常吻合。新方法应该有助于加速与聚集体或附聚物相关的系统的 DEM 模拟。每个粒子的平均配位数和局部堆积分数分布和接触数与使用粒子特性原始值模拟的结果非常吻合。新方法应该有助于加速与聚集体或附聚物相关的系统的 DEM 模拟。
更新日期:2019-01-01
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