Simulations on the flow segregation problem in bidimensional piles

BENITO, J.G.; UÑAC, R.O.; VIDALES, A M; IPPOLITO, I.

Sydney

Congreso; Powders & Grains 2013; 2013

We report a numerical study of the problem of flow segregation in quasi bidimensional piles built up by pouring a mix of grains of two different sizes from a constant height. To simulate the pile formation, we employ two different simulation technics, a Discrete Element Method (DEM) and a pseudo-dynamics method (PSDM). In the case of DEM, the interaction force parameters between grains are adjusted to represent glass beads and a resistance torque is considered when particles are allowed to roll. The concentration of small and big grains is varied, as well as the height at which they are poured in each virtual experiment. We also try with different size ratios between the beads. The segregation patterns arising after the pile is finished are studied by analyzing the spatial distribution of the grains. Two different segregation indices are defined and evaluated over the piles. A phase diagram is presented, showing the conditions under which the different segregation patterns show up. A comparison of all the results obtained with our own experimental results, is performed. We discuss the patterns and the different conditions for the setting up of segregation and the advantages and limitations of both simulation models.