Effect of van der Waals force cut-off distance on adhesive collision parameters in DEM simulation
Effect of van der Waals force cut-off distance on adhesive collision parameters in DEM simulation
复制标题
DOI：
10.1016/j.powtec.2016.05.020
复制
发表时间：
2016-10
影响因子：
5.2
通讯作者：
Hamed Abbasfard;G. Evans;R. Moreno-Atanasio
中科院分区：
文献类型：
--
作者：
Hamed Abbasfard;G. Evans;R. Moreno-Atanasio
计算机技术的迅速发展使得离散元法（DEM）用于大颗粒体系的模拟成为可能。然而，调整DEM模拟参数，特别是颗粒间力，以获得合理的结果仍然是一个挑战。当粒子表面之间的距离接近零时，这些力中的许多力分散。因此，需要考虑截止距离以避免这样的问题。这项工作提出的结果的计算分析的截止距离的影响，这是需要避免发散的货车的德瓦尔斯力，对一个单一的粒子对一个平面的碰撞。因此，已经研究了截止距离对恢复系数、碰撞持续时间和最大重叠的影响。此外，我们从理论上推导出的最小速度下，颗粒保持粘附到表面（临界速度）作为截止距离的函数的表达式。临界速度的模拟预测在文献中发表的实验数据的范围内。我们证明，截止距离有一个深刻的影响颗粒反弹，因此，仔细选择这个参数时，应模拟散装颗粒的行为。考虑到疏水力通常使用与货车范德华力相同的表达式进行模拟，因此此处给出的结果也可以在疏水力模拟的上下文中考虑。
Rapid advancement in computer technology makes it possible to perform simulations of large particulate systems using Discrete Element Method (DEM). However, it is still a challenge to adjust the DEM simulation parameters, especially the interparticle forces, in order to obtain rational results. Many of these forces diverge as the distance between particle surfaces approaches zero. Therefore, a cut-off distance needs to be considered in order to avoid such a problem. This work presents the results of the computational analysis of the influence of the cut-off distance, which is required to avoid the divergence of the van der Waals force, on the collision of a single particle against a flat surface. Hence, the effect of the cut-off distance on the coefficient of restitution, collision duration and maximum overlap has been studied. In addition, we have theoretically derived an expression for the minimum velocity under which the particle remains adhered to the surface (critical velocity) as a function of the cut-off distance. The simulation predictions of the critical velocity are within the range of experimental data published in the literature. We demonstrate that the cut-off distance has a profound influence on particle rebound and therefore, a careful selection of this parameter should take place when simulating bulk particle behaviour. Given that the hydrophobic force is usually simulated using the same expression as the van der Waals force, the results presented here could also be considered in the context of the simulation of the hydrophobic force.