timeVaryingMassSorption

Description

The timeVaryingMassSorption is a boundary condition that provides a first order fixed-value condition for a given scalar field to model time-dependent adsorption-desoprtion processes to be used with the interfaceOxideRate mass model

$$\frac{d c}{d t} = k_{abs} w (c_{int} - c_{p_{w}}) + k_{des} (c_{p_{w}} - c_{int})$$ $$w = \max(1 - c_{p_{w}}/max, 0)$$

where:

Property	Description
$c_{int}$	Concentration at cell
$c_{p_{w}}$	Concentration at wall
$k_{abs}$	Adsorption rate constant [1/s]
$k_{des}$	Desorption rate constant [1/s]
$w$	Weight function
$max$	Max concentration at wall

Usage

The condition requires entries in both the boundary and field files.

Boundary file

<patchName>
{
    type            patch;
    ...
}

Field file

<patchName>
{
    type        timeVaryingMassSorption;
    kbas        <scalar>;
    max         <scalar>;

    // Optional entries
    kdes        <scalar>;

    // Inherited entries
    ...
}

where:

Property	Description	Type	Required	Default
type	Type name: timeVaryingAdsorption	word	yes	-
kbas	Adsorption rate constant	scalar	yes	-
max	Maximum concentation at wall	scalar	yes	-
kdes	Desorption rate constant	scalar	no	0

The inherited entries are elaborated in:

• fixedValueFvPatchField.H

Further information

Tutorial:

• oxideFormation

Source code:

• timeVaryingMassSorption

API:

• Foam::timeVaryingMassSorptionFvPatchScalarField

History: Introduced in version v2106