Two-dimensional sedimentation

The settling of solid particles in a flowing suspension in two-dimensional continuous sedimentation has been studied. The properties of the suspension are analysed from batch settling experiments. In analysing the properties of the suspension, an expression is presented that correlates the data of b...

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Bibliographic Details
Main Author: Onwuchekwa, J. K.
Published: Swansea University 1980
Subjects:
Online Access:http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638370
Description
Summary:The settling of solid particles in a flowing suspension in two-dimensional continuous sedimentation has been studied. The properties of the suspension are analysed from batch settling experiments. In analysing the properties of the suspension, an expression is presented that correlates the data of batch settling experiments. The expression includes the minimum settling parameters, initial linear rate of settling, initial porosity and the free settling velocity in gravity sedimentation. An optical technique for measuring the concentration of solid particles without disturbing the flow field of the suspension has been developed. The method is applicable to high solid particle concentration and has a reproducibility of 4% at higher concentrations of solid particles. A theory which considers forces acting in the flow of suspended solid particles in continuous sedimentation is presented. The porosity distribution measured experimentally is compared with the distribution, computed by numerical solution of the model equations. The flow patterns of both solid and liquid phase have been determined theoretically and are illustrated by streamline plots, constructed with the aid of a contour program. The experimental porosity distribution is also presented in contour form. Both theory and experimental observation show the importance of the operating conditions, that is the feed rate, feed porosity, overflow rate and underflow rate on the performance of a sedimenting system.