On the continuum modeling of dense granular flow in high shear granulation

• Solid viscosity is modeled with an analogy to molecular systems at phase transition.
• The framework is evaluated for the use in high-shear granulation.
• Comparing to previously used models, improvements are seen in all studied variables.
• Coexistence of quasi-static and fluid regimes is successfully captured by the model.
• A dissipative boundary condition better reproduces experimental findings.

This article addresses the subject of continuum modeling of dense granular flows with an application in high shear granulation. The possible use of continuum models and their ability to reproduce correct dynamics of such flows has been a subject of debate for a long time in the literature, and no consensus has been achieved so far. In this paper, we examine and compare two ways for making it possible to study dense granular flows in a continuum framework: the one that considers the stress tensor of a particulate phase as a sum of frictional and kinetic-collisional terms and the one that is based on modification of transport coefficients of the kinetic theory of granular flow. The latter framework is based on an analogy with molecular systems and how they behave at the phase transition from a liquid to a crystalline state. We show here that the formulation proposed in this work is able to correctly capture the phase transition and coexistence of solid-like and fluid-like phases in dense granular flows. This is in contrast to the model with added friction where the stress-strain dependence is shown to give a qualitatively different behavior compared to experimental data.

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