Abstract
This review provides an overview of development and Computational Fluid Dynamics (CFD) analysis of asymmetric straight-through microchannel (MC) emulsification. Asymmetric straight-through MC arrays, each consisting of a circular MC (inlet side) and a microslot (outlet side), were newly designed for stably producing monodisperse emulsions at droplet productivities higher than previously designed grooved MC arrays and symmetric straight-through MC arrays. Silicon asymmetric straight-through MC array chips were precisely fabricated through repeated processes of deep reactive ion etching. Development of asymmetric straight-through MC emulsification devices and their fundamental characteristics are first described. Monodisperse emulsions were successfully produced via appropriately surface-treated asymmetric straight-through MCs at maximum dispersed-phase fluxes of >1,000 L/(m2 h). Production of monodisperse food-grade emulsions using asymmetric straight-through MC arrays as well as their stability evaluation after layer-by-layer deposition are next introduced. The findings obtained from three-dimensional CFD simulation of droplet generation via asymmetric straight-through MCs are also described. The CFD analysis elucidated that droplet detachment process consisted of three important stages that depend on the internal pressure balance of the dispersed phase in and over the slot.
