FEM simulation of particle flow and convective mixing in a cylindrical bladed mixer

The continuum approach of the Eulerian finite element method (FEM) is used to investigate the complex granular flow and mixing in a cylindrical bladed mixer (CBM). The method is verified by comparing various features of the solids flow reproduced by FEM, such as the formation of heaps, the recirculating flow around blades and the spatial distributions of velocities, with those from DEM. A convective mixing model based on FEM is proposed to describe the evolution of mixing pattern as well as mixing index. It is shown that the FEM results of granular flow can agree well with those from DEM. However, due to the lack of a physical law to describe the particle diffusion such as random walk and percolation, the simulated mixing index is only of qualitative implication at present. While much work will be needed in the future, the FEM approach allows the investigation of general solids flow and convective mixing behaviours in large-scale mixers and can serve as a sound basis for ultimately establishing a predictive capability of particle mixing.