Wettability Interaction on Two-Phase Flow in Microfluidic Flow-Focusing Geometry
Authors :- Rakesh Majumder & Gautam Choubey
Publication :- Advances in Thermal Sciences Select Proceedings of ICFAMMT 2022, Lecture Notes in Mechanical Engineering, Springer
The underlying mechanism related to microfluidic two-phase flow system under the surface wettability conditions is getting more attention for both chemical and biological applications. The current study computationally explores the interaction of physicochemical determinants such as capillarity and surface wettability on the microfluidic behaviors of two immiscible fluids flowing in a flow-focusing apparatus with two types of cross-junction angle arrangements (α=90∘ and α=60∘) using volume of fluid (VOF) method utilizing OpenFOAM environment. With an aim to investigate the temporal behavior of dispersed phase with its resulting phenomena such as dripping and jetting, three non-wetting scenarios with a combination of three capillary numbers (Ca) are chosen. The findings reveal that the dripping flow behavior lasts for all non-wetting circumstances at lower capillary numbers. However, the dripping transits to jetting flow pattern by the alteration from lower to higher non-wetting scenario (super-hydrophobic) at higher capillary number. Further, various important phenomena such as pinch-off time and pressure field variation for both junction angles are also illustrated in detail. Such findings indicate that surface wettability acts as a crucial governing parameter that may have important implications for the creation of microfluidic droplet-based systems.