The Laminar Three-Phase Flow, Phase Field Interface
The Laminar Three-Phase Flow, Phase Field interface (), found under the Multiphase Flow>Three-Phase Flow, Phase Field branch (), is a multiphysics interface designed to track the interfaces between three immiscible and incompressible fluids. The flow is assumed to be laminar, that is, to be of low to moderate Reynolds number. The density of each fluid is assumed to be constant, but the there is no restriction on the density differences between the separate fluids.
When adding the Laminar Three-Phase Flow, Phase Field multiphysics interface, a Laminar Flow and a Ternary Phase Field interface are added to the Model Builder. In addition the Multiphysics node, including the multiphysics coupling feature Three-Phase Flow, Phase Field is added.
The Multiphysics Branch in the COMSOL Multiphysics Reference Manual.
Simulations using the Laminar Three-Phase Flow, Phase Field interface are always time-dependent since the position of an interface is almost always dependent of its history.
Interface Properties
Turbulence Model
Since the Three-Phase Flow, Phase Field interface assumes laminar flow, the Turbulence Model property in the Laminar Flow interface is deactivated when the interface is added as a part of a multiphysics interface.
Multiphysics Coupling Option
Laminar Flow interfaces coupled to a Three-Phase Flow, Phase Field interface contains a Multiphysics coupling option property to control the form of the continuity equation. Adding the Three-Phase Flow, Phase Field interface Multiphysics coupling option is automatically set to Ternary Phase Field. In this case the following form of the continuity equation, appropriate for high density difference mixtures is used
(7-2)
When Multiphysics coupling option is set to None, the form of the continuity equation follows the definitions in Theory for the Single-Phase Flow Interfaces.