Investigation of axial segregation in a rotating drum

A binary mixture of particles is used to investigate axial segregation in a rotating drum. The effects of the rotational speed, the fill level, the particle size ratio and the resilience of particles on the segregated band widths are evaluated. When rigid glass particles 0.35 mm or 0.70 mm as the key components are mixed particles with a size ratio of 2, 3, or 4, the dimensionless band width is less affected by the rotational speed, except at fill levels 10% and 20% with 0.35 mm particles as the key components. The dimensionless band width decreases with the increase of the level of fill. Experimental results show that there exists a size ratio where the dimensionless band width has a minimum value using rigid particles. The value is approximately 3. The existence of this value was attributed to the diffusion and inertia mechanisms of the motion of a single particle. A comparison was made on the influence of the fill level and the speed of rotation on the dimensionless band width using rigid glass beads and non-rigid rubber particles. The dimensionless band width increases with the increase of the level of fill using 1 mm rubber particles as the key components with a size ratio 2 at all rotational speeds studied. Whereas the dimensionless band width decreases with increasing level of fill when 1 mm glass particles as the key components with a size ratio 2 are mixed at all rotational speeds studied. When particles of different elastic properties are mixed, segregated bands are formed but are less pure compared to the bands formed due to size segregation. The interfaces between the rubber-rich bands and the glass-rich bands are curved. A remarkable convective motion at the surface of the particle bed is observed.