Evolution of wet agglomerates inside inertial shear flow of dry granular materials

Abstract

We use particle dynamics simulations to investigate the evolution of a wet agglomerate inside homogeneous shear flows of dry particles. The agglomerate is modeled by introducing approximate analytical expressions of capillary and viscous forces between particles in addition to frictional contacts. During shear flow, the agglomerate may elongate, break, or be eroded by loss of its capillary bonds and primary particles. By systematically varying the shear rate and surface tension of the binding liquid, we characterize the rates of these dispersion modes. All the rates increase with increasing inertial number of the flow and decreasing cohesion index of the agglomerate. We show that the data points for each mode collapse on a master curve for a dimensionless scaling parameter that combines the inertial number and the cohesion index. The erosion rate vanishes below a cutoff value of the scaling parameter. This leads to a power-law borderline between the vanishing erosion states and erosion states in the phase space defined by the inertial number and the cohesion index.

Deagglomeration of cohesive particles by turbulence

“…Several models have recently been developed for deagglomeration due to rotary stress in simple shear flows (Dizaji, Marshall & Grant 2019; Ruan, Chen & Li 2020; Vo et al. 2020). The mechanisms responsible for deagglomeration in turbulence, however, are more complicated and less established.…”

Finite‐Size Analysis of the Collapse of Dry Granular Columns

“…Granular materials can behave like a solid, a liquid, or a gas in different circumstances (MiDi, 2004), which increases the difficulty in capturing their macroscopic behavior. Besides, collective structures may form inside a granular system, and the existence and the size of such collective structures (such as bridging, Mehta, 2007; granular agglomerates, Vo, Mutabaruka, et al., 2020; and contact networks, Zhang et al., 2014) will introduce a strong size effect, which further increases the complexity of the problem. In recent decades, breakthroughs have been made to understand the basic governing principles, especially the constitutive relationships, of granular materials (Man & Hill, 2021; MiDi, 2004; Trulsson et al., 2012; Vo, Nezamabadi, et al., 2020), where the behavior of granular materials or granular‐fluid mixtures is considered to be described by dimensionless numbers expressed as the ratio between dominating stresses.…”

Frictional weakening induced by cohesion: the numerical case of cohesive granular failures

“…In this context, discrete numerical simulations can be of great help. Although adding cohesive forces in the contact model may actually prove non-trivial [13,14], consistent simulations allow for probing systems behaviour over a large range of parameters [15][16][17][18][19][20].…”