A Lattice Boltzmann Model Simulating Hydrodynamics of Particle-laden Aqueous Foams and Emulsions

A mesoscopic two component, 2D Lattice Boltzmann Model (LBM) with long-range repulsive and frustrated short-range attractive interactions is implemented to capture the topological changes in multiphase foams and emulsions with particles suspended within the liquid and/or vapor phases in a Hele-Shaw geometry. The model is first validated by simulating the dynamics of a single-suspended particle on a planar liquid-vapor interface and Poiseuille flow of liquid. Initial foam interfaces are being modeled by 2D Voronoi tessellations or images directly captured by Foam analyzer or a Flow-focusing microfludic device used to generate the monodisperse bubbles. As the fluid drains out, the wet to dry foam transition is observed with bubble deformation, coalescence and eventual collapse with the foams start breaking at the top of the cell. However, this transition and bubble coalescence process is drastically reduced in presence of particles of varied hydrophobicity. The effect of short-range structural repulsion forces along with Van-der Waals Attraction and Electrical Double layer repulsion forces in an extended DLVO theory is further investigated for particles dispersed in the foam/emulsion.