The Dispersed Two-Phase Flow, Diluted Species (
) multiphysics coupling is used to simulate the fluid flow of a liquid containing a dispersed phase, together with mass transport occurring in the continuous phase and the dispersed phase. The coupling feature also support mass transfer (solute extraction) between the phases.
The Dispersed Two-Phase Flow, Diluted Species coupling synchronizes the features in a Mixture Model interface, with those in the transport interfaces for each of the phases (
Continuous Phase Transport of Diluted Species and
Dispersed Phase Transport of Diluted Species). When added, the velocity field and the volume fraction of each of the phases, computed by the Mixture Model interface, is synchronized to the species transport interface for each phase.
Use the check boxes to select which of the species that can be dissolved in both phases and is subjected to extraction. When multiple species are present in each phase, the species in the two mass transport interfaces are paired by position, from top to bottom, in the Concentrations list (in the
Dependent Variables section when selecting an interface). During extraction, the species in the continuous phase physics interface is transferred into, or from, the corresponding species in the dispersed phase physics interface. The rate at which species is removed from the continuous phase is
where cc and
cd are the concentration in the continuous and the dispersed phase respectively.
Kp is the partition coefficient determining the phase partitioning at equilibrium,
as is the dispersed phase specific surface area (m
2/m
3), and
km is a mass transfer coefficient governing the transport from the bubble or droplet surfaces to the bulk of each phase. Note same source term but with opposite sign is added for the corresponding species in the dispersed phase.
When modeling phase transfer with a net mass change between the phases, and a corresponding change in the particle radius, Solve for interfacial area can be enabled in the settings of the coupled Mixture Model interface. In this case the resulting specific area is used in the extraction rate.
When a turbulence model is used, the Dispersed Two-Phase Flow, Diluted Species coupling applies turbulence modeling for species transport interface in the following manners:
The Label is the default multiphysics coupling feature name.
The Name is used primarily as a scope prefix for variables defined by the coupling node. Refer to such variables in expressions using the pattern
<name>.<variable_name>. In order to distinguish between variables belonging to different coupling nodes or physics interfaces, the
name string must be unique. Only letters, numbers, and underscores (_) are permitted in the
Name field. The first character must be a letter.
The default Name (for the first multiphysics coupling feature in the model) is
dds1.
The Dispersed Two-Phase Flow, Diluted Species coupling is automatically defined on the intersection of the selections for the coupled interfaces.
The Selection list displays the domains where the coupling feature is active.
This section defines the physics involved in the multiphysics coupling. The lists Dispersed Two-Phase Flow,
Continuous phase species, and
Dispersed phase species include the applicable physics interfaces of each kind.
You can also select None from either list to uncouple the node from a physics interface. If the physics interface is removed from the
Model Builder, for example
Mixture Model, Laminar Flow is deleted, then the
Dispersed Two-Phase Flow list defaults to
None as there is nothing to couple to.
Click the Go to Source buttons (
) to move to the main physics interface node for the selected physics interface.
where μT is the turbulent viscosity defined by the flow interface, and the turbulent Schmidt number,
ScT, depends on the
Mass transport turbulence model used.
and the particle radius rp in the manner of
