Studies of diffusional mixing in rotating drums via computer simulations

Particle diffusion in rotating drums is studied via computer simulations using a full 3-D model which does not involve any arbitrary input parameters. The diffusion coefficient for single-component systems agrees qualitatively with previous experimental results. On the other hand, the diffusion coefficient for two-component systems is shown to be a highly nonlinear function of the rotation velocity. It is suggested that this results from a competition between the diffusive motion parallel to, and flowing motion perpendicular to the axis of rotation.