On continuum modelling of dense inelastic granular flows of relevance for high shear granulation

• Continuum models for dense inelastic granular flows are developed and evaluated.
• A Couette cell is studied as a representative dense inelastic granular system.
• A new radial distribution function for dense inelastic systems is proposed and evaluated.
• The new model is shown to capture particle clustering in a homogeneous cooling granular gas.
• The new model significantly improves predictions for velocity profiles in the cell.

This article investigates a number of possible formulations of a continuum description for modelling dense inelastic granular flows. The revised Enskog theory (RET) for expressing the granular temperature and formulation of transport coefficients has been used within the continuum framework. The framework assumes particles as inelastic spheres and can describe a granular system at a wide range of volume fractions. The transport coefficients depend on the volume fraction through a modified expression for the radial distribution function. The proposed radial distribution function is based on previous studies on the behaviour of the shear viscosity in which an earlier divergence of the latter compared to the other transport coefficients has been demonstrated for sheared dense granular systems. Our results show that the newly developed radial distribution function maintains the ability of RET to predict the occurrence of instabilities in a homogeneous cooling granular gas. The introduced function also improves predictions for the velocity and volume fraction profiles in a Couette cell dense shear flow. Thus the proposed expression shows promising features in terms of improving predictions for volume fractions relevant in high shear granulators. We have also observed that a different expression may be needed for the densest regions.

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