Abstract
By means of extensive particle dynamics simulations in three dimensions, we investigate the rheology and agglomeration process of granular materials such as wet powders, which involve cohesive and viscous interactions in addition to frictional contact forces. In shear flow simulations, we show that the flow variables such as effective friction coefficient and packing fraction and texture variables such as coordination number and anisotropy can be described as a function of a single dimensionless number that incorporates the inertial, cohesive and viscous forces. We also study the evolution of an agglomerate inside a granular shear flow of dry particles and in a rotating drum containing wet particles. The evolution of the agglomerate depends on the accretion and erosion dynamics, which are governed by cohesive interactions. We determine the phase-space diagrams in terms of the agglomerate growth, deformation, damage and erosion as a function of the cohesion index and inertial number. The compressive strength of the agglomerates is also investigated under diametral compression and shown to be proportional to the adhesion force between the particles with a pre-factor that depends on the connectivity of the primary particles.