Effect of Size Ratio on Permeability and Local Packing Fraction of the Binary Packed Bed

The binary-sized packed bed is studied numerically to determine the equivalent permeability of the packed bed. In this study, the ratio of large to small particles diameter (i.e. size ratio, SR) lies between 1 and 10. Various models for correlating the permeability of the binary packed bed from the literature are compared with the present DEM–CFD result. We have studied the effect of size ratio (1 ≤ SR ≤ 10) on the local packing fraction and the permeability of the packed bed. The numerical result compares the different models stated in the literature for predicting the permeability very well for the size ratio in the range of 1–10. The paper also presents a DEM–CFD methodology to simulate the flow through the binary packed bed. The open-source software, LIGGGHTS, simulates the particle filling under gravity, and then, the open-source computer-aided design modeller, FreeCAD, is used to create the packed bed. The meshing and numerical simulation are performed with C++-based CFD toolbox, i.e. OpenFOAM. Further, a comparison of local packing distribution is made for different size ratios at volume fraction of large particle (VFL) ~ 40%.