2D DEM simulation of particle mixing in rotating drum: A parametric study

Mixing behaviors of equal-sized glass beads in a rotating drum were investigated by both DEM simulations and experiments. The experiments indicated that higher rotation speed can significantly enhance mixing. The particle profiles predicted by 2D DEM simulation were compared with the experimental results from a quasi-2D drum, showing inconsistency due to reduction of contacts in the single-layer 2D simulation which makes the driving friction weaker than that in the quasi-2D test, better results could be reached by specifying a higher frictional coefficient between the particles and the cylinder wall. In order to explore the influences of physical properties (density, size or friction) on mixing behavior, numerical 2D simulations were carried out systematically, in which one examined specific property being examined was exaggerated while the others were kept the same as that in the control group. The DEM simulations reveal that particle density and size are the dominating factors affecting mixing behaviors, while the effect of frictional coefficient is less significant. However, segregation due to any of the factors can be diminished by specifying a proper particle size distribution (multi-size with lower size ratio).