Granular flow dynamics on vibrating screens: A mechanistic study

This paper tests a granular flow model developed to describe material transport on an inclined vibrating screen. The model captures three distinct flow regimes: quasi-static, kinetic, and turbulent, based on particle bed depth (h), solids concentration (∅), and particle velocity (u). Discrete Element Method (DEM) simulations were performed on binary granular mixtures (3 mm and 5 mm particles) using a vibrating screen with 3.5 mm apertures under base conditions of 4 Hz frequency and 1 mm amplitude. A coarse graining method was applied to transition microscopic flow properties into macroscopic fields, enabling the analysis of volume fraction and tangential velocity across the flow depth. The model also incorporates an effective friction coefficient that accounts for frictional, collisional, and turbulent stresses. The results demonstrate that increasing vibration intensity transitions the system from a quasi-static regime to more energetic regimes, enhancing particle mobility and improving the percolation of undersized particles. The findings show that 10 Hz promotes the fastest stratification, making it ideal for rapid separation, while 6 Hz and 8 Hz allow for more controlled, gradual stratification, balancing efficiency and turbulence. Lower (4 Hz) and higher (12 Hz) frequencies are less effective due to slower stratification or excessive turbulence. These insights highlight the role of vibration intensity in optimizing screening efficiency and mitigating issues such as aperture jamming. This work evaluates the model's ability to capture flow regime transitions and offers a foundation for optimizing industrial screening processes.