Preventing near-wall particles’ ordering in narrow random packed beds of spheres

Abstract

Packed-bed reactors with small container-to-particle diameter ratios ($D_c/D_p⩽10$) face significant performance challenges due to wall-induced flow maldistribution. The characteristic oscillatory void fraction pattern near container’s wall creates preferential flow paths that compromise reaction uniformity and transport efficiency. While modifications of the container’s wall structure have emerged as a potential solution to this problem, the relationship between the length scales of the modifications and packing homogeneity remains insufficiently explored. This study employs numerical modelling to investigate systematically how regular sinusoidal wall corrugation pattern influences particle arrangement and void fraction distribution in randomly packed beds of spherical particles in relatively narrow beds ($4⩽D_c/D_p⩽10$). In a wide parametric study with respect to the amplitude and wavelength of the corrugation, we demonstrate that properly tuned corrugation patterns can substantially suppress near-wall layering and reduce local void fraction oscillations, promoting more uniform and disordered bed structures. We also observe a geometric resonance phenomenon with respect to the corrugation wavelength near value equal to approximately $1.6D_p$ where the sensitivity of the packing structure to this parameter is particularly pronounced. These findings provide practical design guidance for improving performance in small-scale random packed-bed systems.