The aim of the present work is to investigate droplet formation in a two-dimensional T-Junction microchannel geometry using the open source software OpenFOAM. Two incompressible fluids, air (continuous phase) in the main channel and water (dispersed phase) flow in the lateral channel, have been considered. The InterFoam solver has been used in order to simulate laminar flow with two incompressible and isothermal phases. We evaluate the capability of the volume of fluid technique for modeling of the droplet free surface. We first evaluated the grid size independency of the solution and the suitable mesh for the numerical simulation was determined. Then, the flow behavior in the T-Junction micro-channel over a wide range of capillary numbers (0.0006 to 0.12) in the squeezing, dripping and jetting regimes were examined. In addition, the effect of contact angles was evaluated in a fixed capillary number using constant contact angles of 140, 160, 170 and 180 degrees over all the microchannel walls. We also show that droplet formation process and shape quite depends on the considered contact angle. Moreover, we compare different stages of droplet formation, such as filling, blocking, pinching off and break up.

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