Application of the Polyhedral & Spherical DEM Software, 3DEC& PFC3D, to the Mixing of Granular Material in a Stirred Tank in the Presence of Fluid Flow & a Free Surface

PFC3D, a bonded/granular spherical DEM code, and 3DEC, a rigid/deformable jointed polyhedral DEM code featuring finite-element analysis in each block, are used to model the effect of a fluid medium with a free surface on the mixing of granular material. Spherical particle clumps are used in PFC3D and polyhedral DEM are used in 3DEC to represent the medium. The use of polyhedral DEM instead of spherical DEM adds to the complexity of the search algorithms but offers a better representation of geometry. A common programming language called FISH is used to add the effect of a fluid phase and a free surface to both DEM approaches. A first-order approximation of fluid-particle interaction instead of full-fledged coupling is used to study any enhancement in mixing brought about by the addition of a fluid phase to a stirred tank, and the tradeoff between accuracy and computational efficiency is discussed.