(99a) Static Mixing of Granular MATERIALS

While an understanding of the dynamics of segregation has started to emerge, controlling segregation continues to be a complicated issue. In this study we explore the use of time-modulation ? via selective insert placement as suggested by (Shi, Vargas and McCarthy., PRL, 2007) ? in order to suppress segregation in two geometries intended to be used as static granular mixers. We study bidisperse (size or density), cohesionless granular materials in three and quasi-two dimensional devices by means of simulations and experiments. Results are presented for two configurations of the inserts. Both experiments and simulations indicate that devices whose design is based on the fundamental physics of granular flow are much more effective in reducing segregation, while baffles or inserts whose design is based on empirical observations are less effective in reducing both density and size segregation. Qualitative and quantitative evidence is presented, in terms of the intensity of segregation.