(143a) A DEM Study of Shear Flows of a Binary Mixture of Non-Spherical Particles

Discrete element method (DEM) simulations of shear flows of a binary mixture of large irregular glued-sphere particles and small spheres are conducted in order to investigate the effect of particle shape and solid fraction ratio on the behavior of binary granular flows. The normal and shear stresses first decrease and then increase with total solid fraction. The normal and shear stresses increase with the increasing solid fraction ratio of large particles. However, for dense regions, the stresses for bidisperse systems are lower than those for monodisperse systems, which is due to the lubrication effect of small spheres in the bidisperse system. The orientation distributions of large particles also show that, in dense regions, the bidisperse system with a higher solid fraction ratio of small spheres exhibits a more uniform alignment for large particles. By incorporating the effective particle projective area in the plane perpendicular to the flow plane, the conventional kinetic theory of binary spherical systems is found capable of predicting the stresses for binary systems of non-spherical particles. Stresses for binary systems with various solid fraction ratios, in the dilute and moderately dense regions, collapse into a single line by further incorporating the root-mean-cubed diameter, but this scaling is not adequate for dense flows.