1 DENSE SUSPENSIONS – SOLID-LIQUID INTERACTIONS AT THE PARTICLE SCALE

Flowing solid-liquid suspensions are abundant in natural and engineered systems. In general, solid-liquid flows span a multi-dimensional parameter space, with coordinates such as the Stokes number, the solids volume fraction, the density ratio, and Reynolds numbers. We are interested in systems with appreciable inertia effects – i.e. non-zero Stokes and Reynolds numbers – having density ratios of the order of one (typical for solid-liquid systems) and solids volume fractions of at least 0.1. Additional effects not uncommon in oil & gas and mining applications are strongly inhomogeneous solids distributions, non-Newtonian liquids, sticky particles that tend to aggregate and particles that are non-spherical so that shape effects come into play. This all leads to a rich spectrum of solid-liquid and solid-solid interactions at the scale of individual particles. To reveal these interactions we perform direct simulations of collections of a few thousand of particles carried by a liquid flow with resolution of the solid-liquid interfaces. For this we use the lattice-Boltzmann method supplemented with an immersed boundary approach. Applications such as turbulence-particle interaction, and aggregation of solid particles are discussed