多孔介质随机堆积填充床内流体流动的数值模拟研究

Numerical Simulation of Fluid Flow in Packed Bed within Randomly Packed Structure of Porous Media

采用离散单元法(DEM)构建了多孔介质填充床内颗粒随机堆积结构,运用计算流体力学(CFD)对填充床内部的流体流动进行数值模拟,探究不同入口速度下床层内部流体流动的分布规律。结果表明:在小管径-粒径比填充床的床层中心截面处,流速分布存在局部不均匀性,颗粒表面和床层末端出现了明显的漩涡,床层末端处的漩涡几乎占满了整个流道;随着进口速度的增加,床层颗粒表面的漩涡个数增加,床层内部速度变化剧烈,有利于不同流体的互相掺混。

In this paper,the Discrete Element Method(DEM)was applied to construct the randomly packing structure in the packed bed,and the Computational Fluid Dynamics(CFD)was utilized to numerically simulate the fluid flow inside the packed bed.We also investigated the fluid flow distribution inside the packed bed at different inlet velocities.The results show that the velocity distribution has local inhomogeneity at the center section of the packed bed with low tube-to-particle diameter ratio,and the eddies can be obviously observed on the particle surface and at the end of the bed,especially at the end of the bed,which almost occupy the entire tube.With the increase of inlet velocity,the number of eddies on the particle surface are also increased.