Budget analysis of a pseudo-single-phase transport model for slurry flows

This study aims at understanding the influence of the various physical mechanisms involved in the transport of solid particles within slurry flows. The present model simulates such mixtures as pseudo-single-phase fluids. The approach is based on a constitutive equation, which accounts for the shear-induced particle migration. Two supplementary terms are added to this equation to account for particle buoyancy and turbulent dispersion, respectively. The present model is validated against experimental data published in the literature, and the influence of each mechanism is discussed in detail for two particle diameters $d=125$ and $440\mu m$ and bulk Reynolds numbers $Re$ ranging between 46,000 and 109,000. The detailed budget analysis of the present transport equation reveals that the terms accounting for the particle transport due to the viscosity variation and the particle collision frequency variation get preponderant in the near-wall regions. This last term is besides at the origin of the repelling phenomenon. The turbulent agitation term counterbalances the sedimentation effect. When the convective flux term is important in the bulk region, the flow tends to be homogeneous. The present model can be used confidently to model two-phase flows under certain multiphase flow regimes while requiring less computational efforts than other more complex two-phase models.