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setupRadiation

Specify radiation parameters for surface-to-surface heat transfer

Since R2023b

    Description

    fem = setupRadiation(fem) enables surface-to-surface radiation analysis using the enclosure formed by all faces of the specified model. An enclosure is a group of surfaces between which heat transfer occurs due to radiation without conductive media. The function creates a surfaceToSurfaceSettings object and returns the specified model, fem, with its ThermalRadiation property set to that object.

    example

    fem = setupRadiation(fem,Name=Value) specifies additional options using one or more name-value arguments. For example, you can specify the faces to form enclosures, the enclosure names, and their perfectness.

    Examples

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    Specify radiation parameters for heat transfer between two parallel plates.

    Create the geometry representing two parallel plates of the same dimensions. The distance between the plates is 0.4 m.

    dist = 0.4;
    W = 0.05;
    L = 0.5;
    H = 0.5;
    R1 = [3 4 0 W W 0 0 0 L L];
    R2 = [3 4 W+dist 2*W+dist 2*W+dist W+dist 0 0 L L];
    geom2D = fegeometry(decsg([R1(:) R2(:)], ...
                        'R1+R2',[char('R1')' char('R2')']));
    geom3D = extrude(geom2D,H);
    pdegplot(geom3D,FaceLabels="on",FaceAlpha=0.3)

    Create a finite element model for thermal analysis and include the geometry.

    fem = femodel(AnalysisType="thermalSteady",Geometry=geom3D);

    Generate a mesh.

    fem = generateMesh(fem,Hmax=H/4);

    Account for surface-to-surface radiation in the enclosure formed by the plates by using the setupRadiation function.

    fem = setupRadiation(fem,EnclosureFaces=[5 6]);
    fem.ThermalRadiation
    ans = 
      surfaceToSurfaceSettings with properties:
    
                    ViewFactors: [204×204 double]
                     Enclosures: dictionary (string ⟼ enclosureDefinition) with 1 entry
        ParticipatingEnclosures: "Enclosure_1"
    
    

    If you do not specify enclosure names, setupRadiation uses the default names, such as "Enclosure_1". The function also sets the enclosure perfectness to true, which means that the solver ignores ambient radiation. To change these settings, use the EnclosureNames and PerfectEnclosure name-value arguments.

    fem = setupRadiation(fem,EnclosureFaces=[5 6], ...
                            EnclosureNames="two_plates", ...
                            PerfectEnclosure=false);
    fem.ThermalRadiation
    ans = 
      surfaceToSurfaceSettings with properties:
    
                    ViewFactors: [204×204 double]
                     Enclosures: dictionary (string ⟼ enclosureDefinition) with 1 entry
        ParticipatingEnclosures: "two_plates"
    
    

    Specify ambient temperature and emissivity for the enclosure formed by the plates.

    fem.FaceLoad([5 6]) = faceLoad(AmbientTemperature=0,Emissivity=0.5);

    Input Arguments

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    Finite element model, specified as an femodel object.

    Name-Value Arguments

    Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

    Example: fem = setupRadiation(fem,EnclosureFaces=[5 6],EnclosureNames="two_plates")

    Faces to form enclosures, specified as a vector of positive integers for one enclosure in the model or a cell array of vectors of positive integers for multiple enclosures in the model.

    Example: EnclosureFaces={[1 2 50],[68 97]}

    Names of enclosures, specified as a string or a character vector for a single enclosure or a vector of strings or cell array of character vectors for multiple enclosures.

    Example: EnclosureNames=["groupA" "groupB"]

    Data Types: string | char

    Enclosure perfectness, specified as true or false for a single enclosure or a vector of these values for multiple enclosures. Setting perfectness to true ignores ambient radiation.

    Example: PerfectEnclosure=[true false]

    Data Types: logical

    Tips

    • You must generate a mesh before specifying radiation parameters. Call generateMesh before calling setupRadiation.

    • When calling setupRadiation, always use fem as the output argument to assign the resulting surfaceToSurfaceSettings object to the ThermalRadiation property of the model.

    Version History

    Introduced in R2023b