Effects of density ratio, rotation speed, and fill level on density-induced granular streak segregation in a rotating drum

Granular materials segregate because of differences in density, size, surface roughness, or shape, thus causing critical problems in many industries. In this study, we systematically and experimentally investigated the behavior of density-induced granular segregation in a circular thin rotating drum. We studied the effects of the density ratio, rotation speed, and fill level on the behavior of granular streak segregation. We used particle tracking velocimetry and image processing technology to determine the number of petals and the shape index of streak patterns. The results show that the density ratio, rotation speed, and fill level significantly influence the behavior of density-induced granular segregation, and the shape index decreases with an increase in the rotation speed. The passage time elongates when the density ratio is increased. Moreover, the final stable shape index does not increase monotonically with the fill level. The maximum shape index occurs at a fill level of 0.51.