Toward Understanding the Shape Evolution of Random Packings and Its Effect on the Hydraulic Performance of the Packed Column

Gas–liquid flow and pressure drop in a packed column are closely related with the geometric characteristics of the packings. Motivated by the understanding of shape evolution of random packings, particularly the increasing perforation of the packings’ wall, i.e., higher opening hole ratio, the influences of the packing shape, including its individual shape and its stacking configurations, on the performance of the packed column have been investigated by experiments and numerical simulation. The experiments were conducted on three representative packings under three stacking configurations to examine their orientation effects. The results show that the influence of stacking configurations on pressure drop has been reduced with the shape evolution of the random packings from the Raschig Ring and Pall Ring to the Raschig Super-Ring. An angular factor was introduced to quantify the orientation-dependent resistance and incorporated into a modified dry pressure drop model based on Makowiak’s work, which demonstrated improved accuracy. For the randomly stacked configuration, CFD-DEM simulation results show that a higher opening hole ratio could reduce gas maldistribution and increase the proportion of an effective interfacial area. These findings offer insights into the coupling mechanism between individual packing geometry, stacking characteristics, and bed performance and is beneficial to the rational design of high-performance random packings for large-scale separation processes.