Voidage profiles in packed beds of spheres

✍ Scribed by Venneth M.H. Govindarao; G.F. Froment

• Publisher: Elsevier Science
• Year: 1986
• Tongue: English
• Weight: 773 KB
• Volume: 41
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(86)87035-x

✦ Synopsis

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 &out 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 exwrimental methods. The number fractions in the layer next to the one at 0.5 particle diametkr from the waliand at 1.5 particle diameters completely characterize the voidage variations up to a distance of about 2 particle diameters from the wall. In this region the conlining effect of the wall gives rise to these two non-random layers of the spheres. The two number fractions are correlated exponentially with the aspect ratio. Beyond this region, the structure of the packing becomes more and more random, A procedure is suggested for predicting the void fractions at distances between 2 and 4 particle diameters.