Kinematic-wave analysis of particle settling in tube centrifuges

The kinematic-wave theory of particle settling in tube centrifuges is subject to controversy. G. Anestis and W. Schneider 1] made the common assumption that the flow in a rotating tube of large length/diameter ratio can be treated in one-dimensional approximation. Their results have been found in agreement with measurements 2], 3]. However, M. Ungarish 4] performed an analysis of the two-dimensional settling process in the limit of vanishing particle concentration and obtained results that are not in accord with the one-dimensional flow approximation, irrespective of the length/diameter ratio. It is the aim of the present investigation to gain a better understanding of the process. According to this analysis, quasi-one-dimensional kinematic waves are embedded in a two-dimensional bulk flow that is governed by the boundary conditions at the walls of the tube. The results are compared with those of the one-dimensional flow approximation. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)