SPH-DEM simulations of grain dispersion by liquid injection

We study the dispersion of an initially packed, static granular bed by the injection of a liquid jet. This is a relevant system for many industrial applications, including paint dispersion or food powder dissolution. Both decompaction and dispersion of the powder are not fully understood, leading to inefficiencies in these processes. Here we consider a model problem where the liquid jet is injected below a granular bed contained in a cylindrical cell. Two different initial conditions are considered: a two-phase case where the bed is initially fully immersed in the liquid and a three-phase case where the bed and cell are completely dry preceding the injection of the liquid. The focus of this contribution is the simulation of these model problems using a two-way coupled SPH-DEM granularliquid method [M. Robinson, M. Ramaioli, and S. Luding, submitted (2013) and http://arxiv.org/abs/1301.0752 (2013)]. This is a purely particle-based method without any prescribed mesh, well suited for this and other problems involving a free (liquidgas) surface and a partly immersed particle phase. Our simulations show the effect of process parameters such as injection flow rate and injection diameter on the dispersion pattern, namely whether the granular bed is impregnated bottom-up or a jet is formed and compare well with experiments