Numerical investigation of flow patterns and plug hydrodynamics in a 3D T-junction Microchannel

Abstract

A three-dimensional (3D) numerical simulation of two-phase flow liquid/liquid is performed in a rectangular microchannel with a T-junction. The volume of fluid (VOF) method was used under ANSYS Fluent to capture the interface between the two phases. The dynamic mesh adaptation technique together with the assumption of symmetry plane helps us to reduce the computational cost.The study focuses on the flow patterns and hydrodynamics of plugs. So, the influence of the flow rate ratio q , the capillary number Ca , and the viscosity ratio λ on the liquid film, the plug/droplet shape, and velocity are examined here. Particularly, the plug/droplet lengths predicted by the simulation show good agreement with experimental and correlation available in the literature. The results revealed six distinct flow patterns by dispersing water in a continuous phase of silicone oil. By decreasing the flow rate ratio as well as the viscosity ratio, the liquid film thickness increases in the corners and side planes. In turn, this greatly impacts the liquid film velocity and the plug velocity. Furthermore, capillary number (based on two-phase flow velocity UTP) is also shown to have a greater impact than viscosity ratio and flow rate ratio on plug shape, with the tail curvature always larger than the front curvature.