CFD analyses and validation of multiphase flow in micro-fluidic system

Multiphase flows involving the flow of two or more fluids are becoming increasingly important in micro-fluidic systems because of their potential and projected use as micro-reactors, the production and control of emulsion droplets and their use in analytical devices such as the mu TAS systems. In this work we examine the ability of the Volume of Fluid method (VOF model) available in major computational fluid dynamics (CFD) software such as Fluent and used widely in modeling the motion of interfaces in macroscopic systems to model multiphase micro-fluidic systems accurately. In contrast to macroscopic systems multiphase flows in micro-fluidic channels tend to be laminar and dominated by surface tension and wall adhesion. We demonstrate the ability of the VOF model to capture the qualitative and quantitative aspects of multiphase flow in micro-fluidic channels by validating its predictions with experimental observations and/or analytical solutions. The problems for which we have validated the VOF model include the classical case of fluid rise in capillaries and formation of droplets due to the flow of immiscible fluids in a T junction. Based on these results we believe that the VOF model is ideally suited to model many micro-fluidic devices involving the flow of two or more immiscible fluids.