Size-induced axial segregation of binary mixtures in rotating drum of different lengths

Abstract

This study investigates the size-induced axial segregation of binary mixtures in rotating drums, particularly focusing on the effect of drum length. The results indicate that long drums require more time to achieve stable segregation and form more segregation bands. The core region under the free bed surface remains predominantly filled with small particles, indicating that radial segregation occurs simultaneously with the axial segregation. The angle of repose of large particle bands is consistently greater than that of small particle bands, which drives the migration of large particles. Short drums are more sensitive to changes in rotational speed, while long drums with moderate rotational speed promote the formation of segregation bands. The width of small particle bands shows an increasing–decreasing-stabilizing trend with the drum length increasing. An analysis of particle velocities reveals that the characteristics of segregation bands are closely related to the relative velocity difference between large and small particles.