DEM study of particle segregation in a rotating drum with internal diameter variations

Discrete Element Method (DEM) simulations are carried out to study size segregation of binary mixture in a rotating drum with inner diameter variations. The simulation results agree well with the experimental observations, both indicating that larger particle enrichment occurs in the smaller inner diameter regions. The effect of the inner diameter contracting ratio (CR) on the particle dynamics are further studied by 5 CRs. When CR is 0.9, the contracting wall affects the smaller particles through the strengthened percolation mechanism. Smaller particles move towards the dilated larger inner diameter regions. When CR is 0.5 or 0.3, the contracting wall provides additional shearing to the bed and acts as a barrier to the migration of particles of both sizes. The overall effects indicate that concentrating the larger particles in the smaller inner diameter region requiring a smooth inner diameter changing (i.e., CR > 0.7 in this work).