Void fraction distribution in beds of spheres

Abstract

Abstract The radial variation of void fraction within a packed bed of uniform spheres has been found to vary from unity at the wall to about 38% in the interior of large beds. The voidage distribution takes the form of a damped oscillatory wave with the oscillations damped out at about 4½ to 5 sphere diameters from the container wall. The distribution function is essentially independent of whether the container wall is concave or convex. Continuous surfaces within the bed are responsible for local voidage variations similar to those at the container wall. An improved experimental technique is described in detail. The results presented are for a number of cases with D / d varying from 2.6 to infinity, and for boundary walls which are concave and convex.