Microfluidic devices occur in a large variety of applications in chemical, medical and pharmaceutical process such as inkjet printing, DNA chips, lab-on-a-chip technology, micro-propulsion and droplet-based microfluidics. Due to the small size of these microchannel, the flow is dominated by the viscous and interfacial forces more than inertial and gravity forces.

We examine drop, pancake, plug and jet formation of immiscible liquids in a cross-shaped microchannel with direct numerical simulations using the new solver, BLUE, for massively parallel simulations of fully three-dimensional multiphase flows in complex solid geometries. The figure above shows an experimental flow pattern map with few simulations of each new pattern observed. Animation can be seen in:

https://www.youtube.com/watch?v=vaPZYhJCYac

The shape of the microchannel used for this study consists of a combination between a cross-junction shape and a flow focussing. It corresponds of a glass microfluidic device designed by Dolomite (droplet junction chip-190μm of a part number 3000301). This complexe shape is builded by the mean of a module for the definition of immersed solid objects using a static distance function which take into account their interaction with the flow for both single and two-phase flows. This static distance fonction ψ(x, y, z) is positive for the fluid part and negative for the solid part. Here, (x, y, z) stands for the cartesian coordinate. The final structure represented in figure bellow consistes of the iso-value ψ(x, y, z) = 0. Several primitive solid geometry shapes are already implemented in the code such spheres, planes, cylinders and toruses with the add of geometrical operations such interaction and union for each primitive object.