Direct numerical simulations of emulsion flows

Abstract

In this paper, three-dimensional boundary integral computer simulations of emulsions in shear flows are described. Results for ordered BCC emulsions with dispersed-phase volume fractions below the critical concentration are presented. Complex rheological features including: shear-thinning viscosities, normal stress differences, and a nonlinear frequency response are also explored. For deformable drops, pairwise collision produces net cross-flow displacements that govern self-diffusion of drops. We compute trajectories of two interacting drops in shearing and present interesting numerical simulations of three dimensional gravity-induced motion of two drops. The results also demonstrate the feasibility of simulating high-volume-fraction emulsions and foam

On the influence of the hydrodynamic interactions on the aggregation rate of magnetic spheres in a dilute suspension

“…For gravity-induced aggregation of rigid spheres, Davis [4] developed a theoretical model to investigate the influence of van der Waals and Maxwell slip on the collision efficiency for rapid aggregation regimes. Moreover, the collision rates of spherical and deformable drops in a shear flow were calculated [5][6][7]. While the subject of particle aggregation is generally well known, it must be appreciated that the present study is the first one based on a hydrodynamically interacting magnetic suspensions of non-Brownian particles.…”

On the volume conservation of emulsion drops in boundary integral simulations

“…Afterwards, the formulation was modified to investigate the deformation of drops and bubbles in extensional and shear flows [20,21]. From the 90s, three-dimensional BI methods have been successfully used to study different complex multiphase flows, such as drop deformation and drop breakup [22][23][24], hydrodynamics interactions between two or more drops [25][26][27][28], rheological properties of emulsions at both dilute and concentrated regimes [16,[29][30][31][32][33], and flow of viscous drops through constricted capillaries and granular materials to investigate the potential applications of emulsion injection in porous media in enhanced oil recovery methods [34][35][36][37][38][39]. Some modified BI formulations have also been proposed to analyze the densification of concentrated emulsions [40], emulsions in compressible Stokes' flows [41], and magnetic drops under the action of external magnetic fields [42].…”