Charged Species Effects Model Reference

The Charged Species Effects model combined with the Electrostatic Potential model is useful for modeling low-temperature plasma with reacting flow.

Table 1. Charged Species Effects Reference
Theory	See Species Transport: Charged Species Effects and Dilute Solutions (for electromagnetism formulation).
Provided By	[physics continuum] > Models > Optional Models
Example Node Path	Continua > Physics 1 > Models > Charged Species Effects
Requires	Material: Multi-Component Gas or Multi-Component Liquid Reaction Regime: Any (further selections may be required) Flow: Segregated Flow Optional Models: Electromagnetism Electromagnetism: Electrostatic Potential or Electrodynamic Potential
Properties	Key properties are: Charged Species Mobility Dimension. See Charged Species Effects Model Properties.
Activates	Materials	Mobility. See Charged Species Effects Materials and Methods.
	Initial Conditions	Species Specification. See Charged Species Effects Initial Conditions
	Boundary Inputs	Species Specification. See Charged Species Effects Boundary Settings
	Solvers	Charged Species Effects (only available with the Electrostatic Potential model). See Solvers.
	Other	When using the Electrochemical Reactions model and a surface mechanism is present, the Surface Mechanism > Reacting Surface > Bulk Solid Mixture node appears with a pre-defined Bulk Species > e- sub-node underneath. See Reacting Surface Model Reference: Bulk Solid Mixture.

Charged Species Effects Model Properties

Charged Species Mobility Dimension

Specifies the dimension of the mobility of the species.

Area Quantity / Energy Time
Area / Electric Potential Time

Electroneutrality option

Specifies if the overall ionic charge density is strictly enforced as zero or not. When simulating corrosion applications, maintain the default option (Scaling).

Not Enforced: Not Enforced is the default option when using the Electrostatic Potential model or Solid Ion model. A uniform zero ionic charge density is not enforced. However, depending on the setup of other parameters, the overall ionic charge density may already equal zero. This option is appropriate for non-corrosion related applications which do not require electroneutrality.
Scaling: Scaling is the default option when using the Electrodynamic Potential Model. This method ensures that the overall ionic charge density is equal to zero by scaling the ionic charge densities for each species proportionally. When the species have equal charge numbers, the total concentration is not changed by scaling. Simcenter STAR-CCM+ checks the concentration profiles that are set using the concentration dimension property and provides a warning if they are not electrically neutral. This option is appropriate for applications that feature electroneutrality, such as corrosion and etching. See Eqn. (4077).

Charged Species Effects Materials and Methods

Mobility

Available to set for species in the following locations:

Multi-Component [Gas/Liquid] > [Gas/Liquid] Components > [species] > Material Properties
Solid Ion > Electrochemical Species Components > [species] > Material Properties


Method	Corresponding Method Node
Nernst Einstein	Nernst-Einstein Species mobilities are computed from the Nernst-Einstein relation Eqn. (4080).

Charge Number

Available to set for species in the following locations:

Multi-Component [Gas/Liquid] > [Gas/Liquid] Components > [species] > Material Properties
Solid Ion > Electrochemical Species Components > [species] > Material Properties


Method	Corresponding Method Node
Elemental Composition (available for segregated species only)	Elemental Composition Displays the read-only Charge of that segregated species which is determined based on the settings of the Elemental Composition material property.
Constant (available for electrochemical species only)	Constant Specifies the Value of the charge on that electrochemical species.

Elemental Composition

Available to set for species in the following locations:

Multi-Component [Gas/Liquid] > [Gas/Liquid] Components > [species] > Material Properties
Solid Ion > Electrochemical Species Components > [species] > Material Properties


Method	Corresponding Method Node
Elemental Composition Method	Elemental Composition Method Provides the Atoms node that you use to adjust the elemental composition and charge of the species component. When you right-click the Atoms node, a dialog appears which you use to add atoms—you can also adjust the charge by adding or removing electrons. To add electrons, select E and set a value for the number of electrons to add. To remove electrons, select E and set a negative value for the number of electrons to remove.

Charged Species Effects Initial Conditions

Species Specification

The method by which you specify the proportions of species that are present.


Method	Corresponding Initial Conditions Node
Mole Fraction	Species Mole Fraction Allows you to specify a composite or constant value for the mole fractions of the species.
Mass Fraction	Species Mass Fraction Allows you to specify a composite or constant value for the mass fractions of the species.
Molar Concentration Only available for continuums in which the Constant Density model is selected, and the Multi-Component Gas > Material Properties > Density Method is set to Constant.	Molar Concentration Allows you to specify a composite or constant value for the molar concentrations of the species.

Charged Species Effects Boundary Settings

Inflow or Outflow

Species Specification

The method by which you specify the proportions of species that are present.


Method	Corresponding Physics Value Nodes
Mole Fraction	Species Mole Fraction Allows you to specify a composite or constant value for the mole fractions of the species.
Mass Fraction	Species Mass Fraction Allows you to specify a composite or constant value for the mass fractions of the species.
Molar Concentration Only available when the boundary is associated with a continuum in which the Constant Density model is selected, and the Multi-Component Gas > Material Properties > Density Method is set to Constant.	Molar Concentration Allows you to specify a composite or constant value for the molar concentrations of the species.

Wall

Wall Species Option

The wall species option for a boundary allows you to define what happens to species at that boundary.


Method	Corresponding Physics Values Nodes
Impermeable	None
Specified Flux Adds the Wall Species Flux Derivative Option boundary condition.	Species Flux Allows you to specify a species flux profile at the boundary.
Specified Value	Species Mass Fraction Allows you to specify the mass fraction of species at the boundary.
Specified Concentration Value Only available when the boundary is associated with a continuum in which the Constant Density model is selected, and the Multi-Component Gas > Material Properties > Density Method is set to Constant.	Molar Concentration Allows you to specify the molar concentration of species at the boundary.

Wall Species Flux Derivative Option


Method	Corresponding Physics Values Nodes
None	None
Specified	Species Flux Derivative Allows you to specify the derivative of the species flux with respect to the mass fraction value at the wall.

Charged Species Effects Solver Properties

The Charged Species Effects solver is only available when using the Electrostatic Potential model.

Solver Frozen: When On, the solver does not update any quantity during an iteration. It is Off by default. This is a debugging option that can result in non-recoverable errors and wrong solutions due to missing storage. See Finite Volume Solvers Reference for details.
Under-Relaxation Factor: In order to promote convergence, this property is used to under-relax changes of the solution during the iterative process. If residuals show solution divergence or do not decrease, reduce the under-relaxation factor.