Building pathways to full encapsulation processes

Abstract

Encapsulation, i.e. the coating of tiny solid or liquid particles in a liquid film, has received a growing interest among scholars due to its practical applications, especially in food and pharmaceutical industries. Encapsulation technology is used in coating and controlling drug delivery by protecting the active agents from environmental pressures (e.g., heat, oxygen) and unsought colours/odours. In practice, when dealing with solid particles, this process occurs through impacting liquid droplets of the coating material upon the agent particles. While, in reality, droplet and particle can freely move before and after the collision, a vast majority of the previous efforts to characterize drop-particle impact outcomes have considered that one of the two components is stationary. This study numerically investigates the head-on collisions between freely moving droplet of a glycerine-water solution or synthetic fluids, and freely moving dry spherical particles. In order to achieve this results, a novel 2D axisymmetric Level Set simulation includes fluid-structure interaction (FSI) and an arbitrary Lagrangian-Eulerian (ALE) technique The relative impact velocity and drop-to-particle density ratio are varied across the simulation cases to indicate the importance of variations in momentum. These preliminary results indicate that optimising the momentum is a key factor in achieving a full and stable encapsulation, requiring further research.