Micromechanics of agglomeration forced by the capillary bridge: The restitution of momentum

Abstract

The formation of capillary bridge formed by a liquid adsorbate is one of the main reasons for agglomeration in multiphase flows. Agglomeration takes place when the relative momentum of two colliding particles is fully consumed by the bridge. This article presents a theoretical study of the collisions of particles with adsorbed liquid taking into account the influence of capillary and viscous dissipative forces. The article proposes an approximate analytical solution for the dynamics of the bridge formed during the collision, together with a more complete numerical model, which is validated with experimental data. The restitution of the relative momentum of the colliding particles, depending on a series of dimensionless parameters characterizing the bridge, is investigated. A criterion for prediction of agglomeration, or "collision efficiency," in a flow involving cohesive particles is given. An expression is proposed for the coefficient of restitution for the case of collision via a liquid bridge. _ ext 50, v A 0 520:052, v S 0 50:052.The arrows indicate the direction of particle movement.

The collision efficiency of liquid bridge agglomeration

“…The mechanism of particle-particle interaction within a bridge was considered with the use of model reported in Balakin et al (2013). The technique predicts the amount of the relative momentum consumed during the penetration of the bridge by particles.…”

“…The solution of equation of motion for the particles within the bridge was found analytically (Balakin et al, 2013). The bridge restitution coefficients were then set to be dependent on dimensionless parameters that characterize the bridge (given in Table 1):…”

“…An extended analysis designed to evaluate collision efficiency for fractal agglomerates was performed by Brakalov (1987), Potanin (1991), Kusters et al (1997) and Babler (2008). Finally our recent work (Balakin et al, 2013) dealt with collision efficiency of van-derWaals agglomeration determined from a series of EulerianLagrangian simulations.…”

Effects of Combined Sorbitan Monolaurate Anti-Agglomerants on Viscosity of Water-in-Oil Emulsion and Natural Gas Hydrate Slurry

“…The location and amount of water could be an important variable in determining overall cohesive force [22]. Thus excess free water and/or the presence of water film should affect cohesive force [22][23][24][25][26], interparticle aggregation and viscosity. According to the proposed mechanism of anti-agglomeration [3] in oil-dominated systems, Span 20 may disperse water droplets into the oil phase evenly, while another component of AA may interact with hydrate surface to prevent particles from agglomeration.…”

Micromechanics of proppant agglomeration during settling in hydraulic fractures

“…The expression for fluid lubrication in Eq. (23) has a singular point when the particle surface distance x ij approaches zero (Balakin et al 2013;Crowe et al 2011). However, in the DEM code the singularity is avoided by activation of spring-dashpot rebound behavior just before the real particle surfaces come in contact.…”