Electro-Deposition Coating Model Reference

Table 1. Electro-Deposition Coating Model
Theory	See Electro-Deposition Coating Model.
Provided By	[physics continuum] > Models > Optional Models
Example Node Path	Continua > Physics 1 > Models > Electro-Deposition Coating
Requires	Material: Liquid Flow: Coupled Flow or Segregated Flow Space: Three Dimensional or Two Dimensional Optional Models: Electromagnetism Electromagnetism: Electrodynamic Potential Equation of State: Any Time: Implicit Unsteady
Properties	Key properties are: Starting Criterion and Paint Layer Total Resistance Specification. See Electro-Deposition Coating Model Properties.
Activates	Model Controls (child nodes)	Electrical Resistance Offset Minimum Accumulated Specific Surface Charge Minimum Specific Current Squared Time Integral Minimum Specific Electric Current Paint Layer See Electro-Deposition Coating Model: Model Controls.
	Initial Conditions	Paint Electrical Resistance and Paint Layer Thickness. See Electro-Deposition Coating Model Initial Conditions.
	Boundary Inputs	See Electro-Deposition Coating Model Boundary Settings.
	Solvers	Electro-Deposition Coating. See Electro-Deposition Coating Model Solver Properties.
	Field Functions	Accumulated Specific Surface Charge Boundary Specific Electric Current Paint Coulomb Efficiency Paint Density Paint Electrical Resistance Area Paint Electrical Resistivity Paint Layer Thickness Paint Layer Thickness Growth Rate Time Integrated Specific Current Density Squared See Electro-Deposition Coating Model Field Functions.

Electro-Deposition Coating Model Properties

Starting Criterion

Allows you to specify a threshold value after which the paint layer starts to grow.

None
The paint layer starts growing immediately upon running the simulation.
Accumulated Specific Surface Charge
The paint layer starts growing after the value that is set for the time integral of the specific electric current is reached. You can specify a threshold value as a scalar profile for the continuum under the Electro-Deposition Coating > Minimum Accumulated Specific Surface Charge node. If necessary, you can set specific values for each boundary.
Time Integral Specific Electric Current Squared
The paint layer starts growing after the value that is set for the time integral of the square of the specific electric current is reached. You can specify a threshold value as a scalar profile for the continuum under the Electro-Deposition Coating > Minimum Specific Current Squared Time Integral node. If necessary, you can set specific values for each boundary.

Paint Layer Total Resistance Specification

Allows you to select the method by which the resistivity of the paint layer is calculated before the ODE (Ordinary Differential Equation) is solved for the paint layer thickness. You can set the resulting profiles under the Electro-Deposition Coating Model > Paint Layer node.

Differential Equation
Simcenter STAR-CCM+ solves a differential equation Eqn. (4179) to calculate the paint layer resistance using the electrical resistivity that is specified for the paint layer.
Resistivity
Allows you to set the total electrical resistivity of the paint layer from which Simcenter STAR-CCM+ calculates the paint layer resistance by multiplying the total electrical resistivity by the paint layer thickness Eqn. (4180).
Resistance
Allows you to specify an expression for the electrical resistance of the paint layer Eqn. (4181).

Electro-Deposition Coating Model Initial Conditions

Paint Electrical Resistance: Allows you to specify the initial electrical resistance of the painted area as a scalar profile.
Paint Layer Thickness: Allows you to specify the initial thickness of the paint layer as a scalar profile.

Electro-Deposition Coating Model Boundary Settings

Wall Boundary

Electro-Deposition Coating Specification

Specifies the electro-deposition coating method that is used.

Method	Corresponding Physics Value Nodes
None Leaves the boundary uncoated (default).	None
Current Density Applies the coating. The coating uses the continuum values or the custom boundary values, depending on the setting of the Option property.	None

Option	Corresponding Physics Value Nodes
Use Continuum Values Uses values that are specified for the continuum.	None
Specify Custom Values Uses Physics Values that are set for the boundary—which are available to specify when Method for Electro-Deposition Coating Specification is set to Current Density.	You can set the following values as scalar profiles. Electrical Resistance Offset $g$ in Eqn. (4179). Available when the Electro-Deposition Coating property, Paint Layer Total Resistance Specification, is set to Differential Equation. Initial Paint Electrical Resistance $r_{paint}$ in Eqn. (4179) Initial Paint Layer Thickness $h$ in Eqn. (4179) Minimum Accumulated Specific Surface Charge The paint layer only starts to grow when the time integral of the specific electric current reaches this threshold. Available when the Electro-Deposition Coating property, Starting Criterion, is set to Accumulated Specific Surface Charge. Minimum Specific Current Squared Time Integral The paint layer only starts to grow when the time integral of the square of the boundary-specific electric current reaches this threshold. Available when the Electro-Deposition Coating property, Starting Criterion, is set to Time Integral Specific Electric Current Squared. Minimum Specific Electric Current $j_{\min}$ in Eqn. (4182)

Option

Corresponding Physics Value Nodes

Use Continuum Values: Uses values that are specified for the continuum.

None

Specify Custom Values: Uses Physics Values that are set for the boundary—which are available to specify when Method for Electro-Deposition Coating Specification is set to Current Density.

You can set the following values as scalar profiles.

Electrical Resistance Offset: $g$ in Eqn. (4179). Available when the Electro-Deposition Coating property, Paint Layer Total Resistance Specification, is set to Differential Equation.
Initial Paint Electrical Resistance: $r_{paint}$ in Eqn. (4179)
Initial Paint Layer Thickness: $h$ in Eqn. (4179)
Minimum Accumulated Specific Surface Charge: The paint layer only starts to grow when the time integral of the specific electric current reaches this threshold. Available when the Electro-Deposition Coating property, Starting Criterion, is set to Accumulated Specific Surface Charge.
Minimum Specific Current Squared Time Integral: The paint layer only starts to grow when the time integral of the square of the boundary-specific electric current reaches this threshold. Available when the Electro-Deposition Coating property, Starting Criterion, is set to Time Integral Specific Electric Current Squared.
Minimum Specific Electric Current: $j_{\min}$ in Eqn. (4182)

Electro-Deposition Coating Model Solver Properties

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.
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.

Electro-Deposition Coating Model Field Functions

Accumulated Specific Surface Charge: Displays on a surface, the time integral of the specific electric current which is used in the starting criterion duriing the current time step, when the Electro-Deposition Coating property, Starting Criterion, is set to Accumulated Specific Surface Charge.
Boundary Specific Electric Current: See Eqn. (4182).
Paint Coulomb Efficiency: See Eqn. (4182).
Paint Density: See Eqn. (4182).
Paint Electrical Resistance Area: See Eqn. (4179).
Paint Electrical Resistivity: See Eqn. (4179).
Paint Layer Thickness: See Eqn. (4182).
Paint Layer Thickness Growth Rate: See Eqn. (4182).
Time Integrated Specific Current Density Squared: Displays on the surface, the time integral of the square of the specific electric current which is used in the starting criterion during the current time step, when the Electro-Deposition Coating property, Starting Criterion, is set to Minimum Specific Current Squared Time Integral.

Electro-Deposition Coating Model: Model Controls

Any profiles that are specified for the following child nodes are set for the entire continuum, unless custom values are set for individual boundaries.

The Paint Layer node allows you to set material properties specifically for the paint layer, independent of the material properties that you set for the Liquid. Constant values are set for the Coulomb Efficiency, $c_{p a int}$ , and Density, $ρ_{p a int}$ —both in Eqn. (4182) and Eqn. (4183).
A further material property is available to set for the resistivity of the paint layer, $r_{paint}$ , in Eqn. (4179). The particular node that appears depends on the setting that is specified for the Paint Layer Resistance Specification Option:
- When Differential Equation is selected, you can set a profile for the Electrical Resistivity, Eqn. (4179).
- When Resistivity is selected, you can set a profile for the Total Electrical Resistivity , Eqn. (4180).
- When Resistance is selected, you can set a profile for the Electrical Resistance, Eqn. (4181).
The Minimum Accumulated Specific Surface Charge node allows you to specify—for the continuum—a threshold for the time integral of the specific electric current. Above this threshold, the paint layer begins to grow. Available when the Electro-Deposition Coating property, Starting Criterion, is set to Accumulated Specific Surface Charge.
The Minimum Specific Current Squared Time Integral node allows you to specify—for the continuum—a threshold for the time integral of the square of the boundary-specific electric current. Above this threshold, the paint layer begins to grow. Available when the Electro-Deposition Coating property, Starting Criterion, is set to Time Integral Specific Electric Current Squared.
The Electrical Resistance Offset node allows you to specify a scalar profile for $g$ in Eqn. (4179). Available when the Electro-Deposition Coating property, Paint Layer Total Resistance Specification, is set to Differential Equation.
The Minimum Specific Electric Current node allows you to specify a scalar profile for $j_{\min}$ in Eqn. (4182).