(341d) Investigation of Mixing Behavior in Shape-Dependent Polydisperse Mixtures and Critical Length Scale of Percolation in a Vibrating Bed System Using DEM

The present study employs DEM simulation to explore the interplay between shape-dependent size polydispersity, the critical length scale of percolation, and mixing behavior within a vibrating packed bed system. In the realm of mixture types, the investigation differentiates between homogeneous (single shape) and heterogeneous (multiple shapes) mixtures, providing insights into their distinct effects on mixing. Non-spherical particles are generated using Super-quadric methods. Size polydispersity is represented by the standard deviation to mean particle diameter ratio, and the impact of particle shape on mixing are assessed using the Overall Mixing Index (SMI). Findings reveal a decrease in mixing as polydispersity transitions from a narrow to a wide distribution in homogeneous Gaussian mixtures. The investigation delves into the effects of coarse and fine particle shapes—sphere, ellipsoid, cylinder, and cube—on mixing behavior for heterogenous gaussian mixtures. Another focal point of the research is the critical length scale of percolation, representing the minimum size of the dynamic void allowing fine particles to percolate freely in a series of binary mixtures. The study scrutinizes the impact of key particle parameters (shape and size) on this critical length scale. For coarse particle shapes, certain shapes appear to influence the critical length scale differently than others, and the introduction of intermediate-size particles decreases the critical length scale of percolation. A predictive machine learning model has been developed to directly estimate the percentage of percolated fines using input variables such as size ratio and sphericity ratio. By analyzing the percentage of percolated fine particles, the critical length scale of percolation is determined for various combinations of size and sphericity ratios. The results indicate that employing nonspherical particles in the vibrated packed bed system can minimize the critical length scale of percolation. This comprehensive investigation provides insights into the intricate dynamics governing mixing behavior, emphasizing the role of particle size distribution, shape, and percolation phenomena in vibrated packed bed systems.