Microfluidics Module

New App: Inkjet Design

Although initially invented to be used in printers, inkjets have been adopted for other application areas, such as within the life sciences and microelectronics. Simulations can be useful to improve the understanding of the fluid flow and to predict the optimal design of an inkjet for a specific application.

The purpose of the Inkjet Design app is to adapt the shape and operation of an inkjet nozzle for a desired droplet size, which depends on the contact angle, surface tension, viscosity, and density of the injected liquid. The results also reveal whether the injected volume breaks up into several droplets before merging into a final droplet at the substrate.

The fluid flow is modeled by the incompressible Navier-Stokes equations together with surface tension, using the level set method to track the fluid interface.

Screen captures of the pinch-off process during an inkjet simulation. The graphs show the injection-pulse profile (1D) and the time-evolution of the droplet size (2D, 3D). Screen captures of the pinch-off process during an inkjet simulation. The graphs show the injection-pulse profile (1D) and the time-evolution of the droplet size (2D, 3D).

Screen captures of the pinch-off process during an inkjet simulation. The graphs show the injection-pulse profile (1D) and the time-evolution of the droplet size (2D, 3D).

New Multiphase Flow Interface: Three-Phase Flow, Phase Field

The new Three-Phase Flow, Phase Field interface can be used to model the flow and interaction of three different, immiscible fluids when you need to study the exact positions of the interfaces separating the fluids. This phenomenon is also known as separated flow with surface tracking. The fluid-fluid interfaces are tracked using a ternary phase field formulation that accounts for differences in the fluids’ densities and viscosities and includes the effects of surface tension. The phase field method can handle moving contact lines on no-slip boundaries.

The predefined Three-Phase Flow multiphysics coupling combines a Laminar Flow interface with a Ternary Phase-Field interface. The movement of the fluid-fluid interfaces is determined by the minimization of free energy.

Libraries for liquid-liquid and liquid-gas surface tension coefficients are available. In the Wetted Wall feature, you can specify contact angles for fluid pairs at solid surfaces.

A flow between a gas and two liquids, simulated with the Laminar Three-Phase Flow, Phase Field interface. A flow between a gas and two liquids, simulated with the Laminar Three-Phase Flow, Phase Field interface.

A flow between a gas and two liquids, simulated with the Laminar Three-Phase Flow, Phase Field interface.

New Mathematics Interface: Ternary Phase Field

The corresponding Ternary Phase Field interface, used to track moving interfaces between three immiscible phases in the CFD and Microfluidics modules, is also a standalone Mathematics interface.