DEM Study on the Segregation of a Non-Spherical Intruder in a Vibrated Granular Bed

Abstract

The segregation process of a single large intruder in a vibrated bed of small particles has been widely studied, but most previous studies focused on spherical intruders. In this work, the discrete element method was used to study the effects of vibration conditions and intruder shape on the dimensionless ascending velocity (va) of the intruder. The intruder was in a prolate shape with aspect ratio varied but its equivalent diameter fixed. Three equivalent diameters, namely volume-equivalent diameter, surface-area-equivalent diameter, and Sauter diameter, were used. It was found that va increases and then decreases with the rise of the dimensionless vibration amplitude (Ad) and the dimensionless vibration frequency (fd), and va increases with the decrease of the sphericity of the intruder (Φ). Moreover, the porosity variation in the vibrated bed and the granular temperature were analyzed, which can be linked to the change of va. It was further found that va can be uniformly correlated to Ad·fd0.5, while the critical change of the response of va to Ad and fd occurs at Γ = 4.83, where Γ is the vibration intensity. Based on these findings, a piecewise equation was proposed to predict va as a function of Ad, fd, and Φ.