Granular segregation across flow geometries: a closure model for the particle segregation velocity

TL;DR

This paper develops a comprehensive model for particle segregation velocity in dense granular flows, applicable across various geometries, and validated through simulations, enhancing predictive capabilities in industrial and geophysical contexts.

Contribution

A novel segregation velocity model based on momentum balance and particle-scale forces that works across diverse flow geometries and conditions.

Findings

Model accurately predicts segregation velocity in simulations.

Incorporating the model improves segregation predictions in flow systems.

Applicable to industrial and geophysical granular flow scenarios.

Abstract

Predicting particle segregation has remained challenging due to the lack of a general model for the segregation velocity that is applicable across a range of granular flow geometries. Here, a segregation velocity model for dense granular flows is developed by exploiting momentum balance and recent advances in particle-scale modelling of the segregation driving and drag forces over a wide range of particle concentrations, size and density ratios, and flow conditions. This model is shown to correctly predict particle segregation velocity in a diverse set of idealized and natural granular flow geometries simulated using the discrete element method. When incorporated in the well-established advection-diffusion-segregation formulation, the model has the potential to accurately capture segregation phenomena in many relevant industrial application and geophysical settings.