Size-Induced Segregation Characteristics and Phase Transition Processes of Binary Particles in Non-Cylindrical Long Rotary Drums

In this study, the effects of drum geometric boundary conditions on size-induced segregation behaviors of binary particle systems were systematically investigated in non-cylindrical rotary drums. The results indicate that radial percolation effects and axial inclined percolation effects interact within the binary particle system in drums. In a rotary drum with a low filling rate, as the drum shape parameters change, the flow characteristics of binary particle mixtures are inconsistent, exhibiting phenomena such as the formation, reversal, splitting, merging, and replication of axial segregation bands. In contrast, with an increasing number of drum edges, rotary drums with medium filling rates gradually form axial core band characteristics with alternating intervals, while those with high filling rates gradually form axial throughout core band characteristics. Moreover, with the continuous increase in drum filling rate, the particle segregation index shows the first decrease and then increase characteristics in the final stabilization stage. Consequently, once the effects of rotary drum shape parameters and filling rate conditions are combined, the particle segregation characteristics have different phase transition processes corresponding to the different significant regions shown in the final steady segregation index phase diagrams.