Geometrical and topological measures for hydrodynamic dispersion in confined sphere packings at low column-to-particle diameter ratios

Abstract

At low column-to-particle diameter (or aspect) ratio (dc/dp) the kinetic column performance is dominated by the transcolumn disorder that arises from the morphological gradient between the more homogeneous, looser packed wall region and the random, dense core. For a systematic analysis of this morphology–dispersion relation we computer-generated a set of confined sphere packings varying three parameters: aspect ratio (dc/dp=10–30), bed porosity (ɛ=0.40–0.46), and packing homogeneity. Plate height curves were received from simulation of hydrodynamic dispersion in the packings over a wide range of reduced velocities (v=0.5–500). Geometrical measures derived from radial porosity and velocity profiles were insufficient as morphological descriptors of the plate height data. After Voronoi tessellation of the packings, topological information was obtained from the statistical moments of the free Voronoi volume (Vfree) distributions. The radial profile of the standard deviation of the Vfree distributions in the form of an integral measure was identified as a quantitative scalar measure for the transcolumn disorder. The first morphology–dispersion correlation for confined sphere packings deepens our understanding of how the packing microstructure determines the kinetic column performance.