Shape-dependent size polydispersity: DEM investigation of mixing behavior in a vibrating packed bed system

Abstract

The Discrete element method is applied to examine the influence of shape-dependent size polydispersity on mixing behavior in a vibrating packed bed system. A series of tests for optimized simulation settings for evaluation of mixing are performed. The influence of size polydispersity (standard deviation to mean particle diameter ratio) and the particle shape on mixing is assessed using the overall mixing index. The mixtures are differentiated between homogeneous and heterogeneous mixtures. In homogeneous mixtures, continuous (Gaussian) distribution outperforms discrete (binary and ternary). Mixing decreases with size polydispersity transitioning from narrow to wide distributions in homogeneous Gaussian mixtures. For heterogeneous Gaussian mixtures, the mixing trends for fine particle shapes are ellipsoid > sphere > cylinder > cube, while the mixing trends for coarse particle shapes are cylinder > sphere > ellipsoid > cube. Changing intermediate particle shapes in heterogeneous ternary mixtures impacts mixing; the cube shows worst performance.