FLOW AND SEGREGATION OF BINARY MIXTURE OF PARTICLES OF DIFFERENT SHAPE IN A ROTATING HORIZONTAL CYLINDER

The transverse bed motion of a binary mixture of spherical and non-spherical particles in a rotating horizontal cylinder was experimentally investigated in relation to the rotational speed N of the cylinder, the bed height and the mixture ratio of the particles. Particle segregation due to shape difference was also examined. At lower N, bed motions categorized as slipping and slumping occurred and were explained in terms of the angle of repose of the mixtures. At higher N, the cascading and cataracting motions occurred. They could not be explained by the angle of repose alone because of the shape segregation of particles. In the cascading and cataracting flow regions, alternating stripes of particle layers arose along the cylinder axis. The variation in the local mixture ratio became pronounced in the cataracting region.