externalWallHeatFluxTemperature

Description

The externalWallHeatFluxTemperature is a boundary condition that applies a heat flux condition to temperature on an external wall in one of three modes:

• fixed power: supply Q
• fixed heat flux: supply q
• fixed heat transfer coefficient: supply h and Ta

where:

Property	Description
Q	Power [W]
q	Heat flux [W/m^2]
h	Heat transfer coefficient [W/m^2/K]
Ta	Ambient temperature [K]

For heat transfer coefficient mode optional thin thermal layer resistances can be specified through thicknessLayers and kappaLayers entries.

The thermal conductivity kappa can either be retrieved from various possible sources, as detailed in the class temperatureCoupledBase.

Usage

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

Boundary file

<patchName>
{
    type            patch;
    ...
}

Field file

<patchName>
{
    // Mandatory entries
    type            externalWallHeatFluxTemperature;
    mode            <word>;

    // Optional entries
    relaxation      <scalar>;
    emissivity      <scalar>;
    qrRelaxation    <scalar>;
    qr              <word>;

    // Conditional entries

        // if mode==power
        Q           <Function1<scalar>>;

        // if mode==flux
        q           <PatchFunction1<scalar>>;

        // if mode==coefficient
        h           <PatchFunction1<scalar>>;
        Ta          <Function1<scalar>>;
        thicknessLayers <scalarField>;
        kappaLayers <scalarField>;

        // if qr!=none
        qrPrevious  <scalarField>;

    // Inherited entries
    ...
}

where:

Property	Description	Type	Required	Default
type	Type name: externalWallHeatFluxTemperature	word	yes	-
mode	Operation mode	word	yes	-
relaxation	Relaxation factor for wall temperature	scalar	no	1.0
emissivity	Surface emissivity for radiative flux	scalar	no	0.0
qrRelaxation	Relaxation factor for radiative field	scalar	no	1.0
qr	Name of radiative field	word	no	none
Q	Heat power [W]	Function1<scalar>	conditional	-
q	Heat flux [W/m^2]	PatchFunction1<scalar>	conditional	-
h	Heat transfer coeff [W/m^2/K]	PatchFunction1<scalar>	conditional	-
Ta	Ambient temperature [K]	PatchFunction1<scalar>	conditional	-
qrPrevious	Cached field for qr relaxation	scalarField	conditional	-

The inherited entries are elaborated in:

• mixedFvPatchFields.H
• temperatureCoupledBase.H
• PatchFunction1.H

Further information

Tutorial:

• externalSolarLoad

Source code:

• externalWallHeatFluxTemperature

API:

• Foam::externalWallHeatFluxTemperatureFvPatchScalarField

History: Introduced in version 2206