Numerical Investigation of Mixing Inside the Dispersed Phase In Slug Flows In Microchannel

Multiphase slug flows offers unique environment for chemical synthesis at micron scale. The dispersed phase provides controlled environment for chemical reactions with minimal contamination and dispersion effects while intensifying mass transfer due to internal circulations. The influence of parameters such as flow rate, viscosity and geometry on mixing inside the dispersed phase has not been extensively studied and is not well – understood. In this work, we study mixing inside dispersed phase in a T – junction microfluidic device through extensive 3D numerical simulations. The Volume of Fluid (VOF) method is used to study the hydrodynamics of water drop / slug formation in perfluorodecaline (PFD). The numerical model is validated with the previous experimental measurements [Tice, J.D. et al., Langmuir 2003, 19, 9127 - 9133] and found to be in good agreement. We analyze the effect of flow conditions, channel geometry and various other process parameters (fluid properties and composition) on slug length and frequency with emphasis on mixing characteristics inside the dispersed phase. The mixing inside the slug is quantitatively characterized by mixing index for various parametric regimes. The presented results will be useful for designing micro-reactor systems based on slug flows.