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Tangential velocity profiles of granular material within horizontal rotating cylinders modelled using the DEM

Third, J. ; Scott, D. ; Scott, S. ; Müller, C.

In: Granular Matter, 2010, vol. 12, no. 6, p. 587-595

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    Title
    • Tangential velocity profiles of granular material within horizontal rotating cylinders modelled using the DEM
    Author
    • Third, J.. Department of Mechanical and Process Engineering, Institute of Energy Technology, ETH Zürich, Leonhardstraße 27, 8092, Zürich, Switzerland
    • Scott, D.. Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, CB2 3RA, Cambridge, UK
    • Scott, S.. Department of Engineering, University of Cambridge, Trumpington Street, CB2 1PZ, Cambridge, UK
    • Müller, C.. Department of Mechanical and Process Engineering, Institute of Energy Technology, ETH Zürich, Leonhardstraße 27, 8092, Zürich, Switzerland
    Document Type
    • Postprint
    OAI-PMH Identifier
    • oai:doc.rero.ch:315885
    Summary
    Flow regimes of granular materials in horizontal rotating cylinders are industrially important since they have a strong influence on the rates of heat and mass transfer within these systems. The tangential velocity profile, which describes how the average particle velocity in the direction parallel to the surface of the bed varies along a radius perpendicular to the surface of the bed, has been examined for many experimental and simulated systems. This paper is concerned with tangential velocity profiles within rotating cylinders simulated using the discrete element method. For high fill levels good agreement is found between the simulated velocity profiles and the equation proposed by Nakagawa etal. (Exp Fluids 16:54-60, 1993) based on magnetic resonance measurements. At lower fill levels slip is observed between the cylinder wall and the particles in contact with it and also between the outer layer of particles and the bulk of the bed. It is demonstrated that this slip occurs when the particles in contact with the wall are able to rotate and that it may be prevented either by using non-spherical particles or by attaching "lifters” to the cylinder wall