CFD phenomenological model of solid–liquid mixing in stirred vessels

Particle migration in a concentrated viscous suspension subjected to a non-homogeneous shear field was computed using a 3D extension of the diffusion model of Phillips et al. [Phillips, R. J., Armstrong, R. C., Brown, R. A., Graham, A. L., & Abott, J. R. (1992). A constitutive equation for concentrated suspensions that accounts for shear-induced particle migration. Physics of Fluids A, 4, 30–40]. The numerical results were compared to experimental data from the literature for simple flows and to our own data in the case of two helical ribbon based mixing systems. It is shown that this type of diffusion model, which was developed to predict the behavior of concentrated suspensions dominated by particle–particle interactions, can predict migration trends but definitely requires additional improvements.