Numerical simulation for the initial state of avalanche in polydisperse particle systems

Abstract

Numerical simulation is employed to investigate the initial state of avalanche in polydisperse particle systems. Nucleation and propagation processes are illustrated for pentadisperse and triadisperse particle systems, respectively. In these processes, particles involved in the avalanche grow slowly in the early stage and explosively in the later stage, which is clearly different from the continuous and steady growth trend in the monodisperse system. By examining the avalanche propagation, the number growth of particles involved in the avalanche and the slope of the number growth, the initial state can be divided into three stages: T1 (nucleation stage), T2 (propagation stage), T3 (overall avalanche stage). We focus on the characteristics of the avalanche in the T2 stage, and find that propagation distances increase almost linearly in both axial and radial directions in polydisperse systems. We also consider the distribution characteristics of the average coordination number and average velocity for the moving particles. The results support that the polydisperse particle systems are more stable in the T2 stage.