speciesSorption

Description

The speciesSorption is a boundary condition that provides a first-order zero-gradient condition for a given scalar field to model time-dependent adsorption-desorption processes.

$$\frac{d c}{d t} = k_{ads} (c_{eq} - c_{abs})$$

where:

Property	Description
$c_{eq}$	Equilibrium concentration
$c_{abs}$	Absorbed at wall
$k_{ads}$	Adsorption rate constant [1/s]

$$c_{eq} = c_{max} \frac{k_l \, c_{int}}{1 + k_l \, c_{int}}$$

where:

Property	Description
$c_{max}$	Maximum concentration
$k_l$	Langmuir constant
$c_{int}$	Local cell value concentration

Usage

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

Boundary file

<patchName>
{
    type            patch;
    ...
}

Field file

<patchName>
{
    // Mandatory entries
    type                    speciesSorption;
    equilibriumModel        <word>;
    kinematicModel          <word>;
    kabs                    <scalar>;
    kl                      <scalar>;
    max                     <scalar>;
    thickness               <PatchFunction1<scalar>>;
    rhoS                    <scalar>;

    // Optional entries
    dfldp                   <scalarField>;
    mass                    <scalarField>;
    pName                   <word>;

    // Inherited entries
    ...
}

where:

Property	Description	Type	Required	Default
type	Type name: speciesSorption	word	yes	-
equilibriumModel	Equilibrium model	word	yes	-
kinematicModel	Kinematic model	word	yes	-
kabs	Adsorption rate constant [1/s]	scalar	yes	-
kl	Langmuir constant [1/Pa]	scalar	yes	-
max	Maximum concentation at wall [mol/kg]	scalar	yes	-
thickness	Solid thickness along the patch	PatchFunction1<scalar>	yes	-
rhoS	Solid density	scalar	yes	-
dfldp	Source on cells next to patch	scalarField	no	Zero
mass	Absorbed mass per kg of absorbent [mol/kg]	scalarField	no	Zero
pName	Name of operand pressure field	word	no	p

Options for the equilibriumModel entry:

Property	Description
Langmuir	Langmuir model

Options for the kinematicModel entry:

Property	Description
PseudoFirstOrder	Pseudo first-order model

The inherited entries are elaborated in:

• zeroGradientFvPatchFields.H
• PatchFunction1.H
• boundarySourcePatch.H

Further information

Tutorial:

• groundAbsorption

Source code:

• speciesSorption

API:

• Foam::speciesSorptionFvPatchScalarField

History: Introduced in version v2112