VOIDAGE PROFILES IN PACKED-BEDS OF SPHERES

Voidage profiles in randomly packed beds of uniformly sized spheres are analysed by dividing the bed into a number of concentric layers of equal thickness, and by expressing the void fraction in a layer in terms of the contributions to the solid volume by spheres with centres lying in appropriate neighbouring layers. The number of spheres in a layer is expressed as a fraction of the total number in the bed. Sets of number fractions in layers up to a distance of about 4-5 particle diameters from the wall are estimated for different aspect ratios using several sets of reported void fraction data obtained by a variety of experimental methods. This work is pertinent to the design of reactors, absorbers, distillation columns and heat transfer equipment.