Modelling the granular flow in a rotating drum by the Eulerian finite element method

This paper presents a numerical study on the flow behaviours of granular materials in a rotating drum based on the Eulerian-formulation finite element method (Eulerian FEM). The granular material is here assumed to be cohesionless and treated as a continuum medium described by the conventional Mohr-Coulomb elastoplastic model. It is shown that this Eulerian FEM approach can reproduce almost all the particle flow patterns that frequently happen in rotating drum, i.e. slipping, slumping, rolling, cascading, cataracting and centrifuging, provided that the parameters of rotational speed, coefficient of friction and internal friction angle are properly selected. On average, the predicted surface angles of a rotating bed are comparable to the experimental observations (Parker, D.J. et al., 1997. Positron emission particle tracking studies of spherical particle motion in rotating drums. Chem. Eng. Sci. 52, 2011-2022.), but the curvature of surface may be slightly over-estimated for drums comprised by big component particles. Linear distributions of particle velocity are seen along the mid-cord of the bed and agree well with the data published in the literature (Boateng, A.A., 1998. Boundary layer modelling of granular flow in the transverse plane of a partially filled rotating cylinder. Int. J. Multiphas. Flow 24, 499-521). The bulk stress inside the particle bed is also investigated, and its spatial distribution is demonstrated to depend on the rotating speed and other operational parameters.