GapFluxModelRadiation

Gap flux model for heat conduction across a gap due to radiation, based on the diffusion approximation. Uses a coupled temperature variable.

Description

GapFluxModelRadiation computes a radiative heat flux across a gap following the diffusion approximation of radiation physics. This user object must be used in combination with ModularGapConductanceConstraint.

The heat flux across the gap is given by the classical expression (1) where is the Stephan-Boltzmann constant, is an emissivity function, is the surface temperature, is the farfield temperature, and is the radiant gap conductance. This expression can be rearranged to solve for : which reduces to (2)

If the coordinate system type is Cartesian, the emissivity is computed using an infinite parallel plate approximation given by (3) where and are the near surface and farfield emissivity values, respectively. The primary and secondary surface emissivity values can be assigned arbitrarily to and . For an axisymmetric coordinate system, the emissivity is computed using the same formula as that given in FVInfiniteCylinderRadiativeBC:

Here the subscript should correspond to whichever surface (secondary or primary) has the smaller radius, and the subscript should correspond to whichever surface has the larger radius.

Example Input File Syntax

[UserObjects<<<{"href": "../../syntax/UserObjects/index.html"}>>>]
  [radiation]
    type = GapFluxModelRadiation<<<{"description": "Gap flux model for heat conduction across a gap due to radiation, based on the diffusion approximation. Uses a coupled temperature variable.", "href": "GapFluxModelRadiation.html"}>>>
    temperature<<<{"description": "The name of the temperature variable"}>>> = temp
    boundary<<<{"description": "The list of boundary IDs from the mesh where this object applies"}>>> = 100
    primary_emissivity<<<{"description": "The emissivity of the primary surface"}>>> = 1.0
    secondary_emissivity<<<{"description": "The emissivity of the secondary surface"}>>> = 1.0
    use_displaced_mesh<<<{"description": "Whether or not this object should use the displaced mesh for computation.  Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used."}>>> = true
  []
[]
(modules/heat_transfer/test/tests/gap_heat_transfer_mortar/modular_gap_heat_transfer_mortar_displaced_radiation.i)

GapFluxModelRadiation must be used in conjunction with the modular gap conductance constraint as shown below:

[Constraints<<<{"href": "../../syntax/Constraints/index.html"}>>>]
  [ced]
    type = ModularGapConductanceConstraint<<<{"description": "Computes the residual and Jacobian contributions for the 'Lagrange Multiplier' implementation of the thermal contact problem. For more information, see the detailed description here: http://tinyurl.com/gmmhbe9", "href": "../constraints/ModularGapConductanceConstraint.html"}>>>
    variable<<<{"description": "The name of the lagrange multiplier variable that this constraint is applied to. This parameter may not be supplied in the case of using penalty methods for example"}>>> = lm
    secondary_variable<<<{"description": "Primal variable on secondary surface."}>>> = temp
    use_displaced_mesh<<<{"description": "Whether or not this object should use the displaced mesh for computation.  Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used."}>>> = true
    primary_boundary<<<{"description": "The name of the primary boundary sideset."}>>> = 100
    primary_subdomain<<<{"description": "The name of the primary subdomain."}>>> = 10000
    secondary_boundary<<<{"description": "The name of the secondary boundary sideset."}>>> = 101
    secondary_subdomain<<<{"description": "The name of the secondary subdomain."}>>> = 10001
    gap_flux_models<<<{"description": "List of GapFluxModel user objects"}>>> = radiation
  []
[]
(modules/heat_transfer/test/tests/gap_heat_transfer_mortar/modular_gap_heat_transfer_mortar_displaced_radiation.i)

Input Parameters

  • boundaryThe list of boundary IDs from the mesh where this object applies

    C++ Type:std::vector<BoundaryName>

    Controllable:No

    Description:The list of boundary IDs from the mesh where this object applies

  • temperatureThe name of the temperature variable

    C++ Type:std::vector<VariableName>

    Unit:(no unit assumed)

    Controllable:No

    Description:The name of the temperature variable

Required Parameters

  • allow_duplicate_execution_on_initialFalseIn the case where this UserObject is depended upon by an initial condition, allow it to be executed twice during the initial setup (once before the IC and again after mesh adaptivity (if applicable).

    Default:False

    C++ Type:bool

    Controllable:No

    Description:In the case where this UserObject is depended upon by an initial condition, allow it to be executed twice during the initial setup (once before the IC and again after mesh adaptivity (if applicable).

  • execution_order_group0Execution order groups are executed in increasing order (e.g., the lowest number is executed first). Note that negative group numbers may be used to execute groups before the default (0) group. Please refer to the user object documentation for ordering of user object execution within a group.

    Default:0

    C++ Type:int

    Controllable:No

    Description:Execution order groups are executed in increasing order (e.g., the lowest number is executed first). Note that negative group numbers may be used to execute groups before the default (0) group. Please refer to the user object documentation for ordering of user object execution within a group.

  • force_postauxFalseForces the UserObject to be executed in POSTAUX

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Forces the UserObject to be executed in POSTAUX

  • force_preauxFalseForces the UserObject to be executed in PREAUX

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Forces the UserObject to be executed in PREAUX

  • force_preicFalseForces the UserObject to be executed in PREIC during initial setup

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Forces the UserObject to be executed in PREIC during initial setup

Execution Scheduling Parameters

  • control_tagsAdds user-defined labels for accessing object parameters via control logic.

    C++ Type:std::vector<std::string>

    Controllable:No

    Description:Adds user-defined labels for accessing object parameters via control logic.

  • enableTrueSet the enabled status of the MooseObject.

    Default:True

    C++ Type:bool

    Controllable:Yes

    Description:Set the enabled status of the MooseObject.

  • implicitTrueDetermines whether this object is calculated using an implicit or explicit form

    Default:True

    C++ Type:bool

    Controllable:No

    Description:Determines whether this object is calculated using an implicit or explicit form

  • use_displaced_meshTrueWhether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.

    Default:True

    C++ Type:bool

    Controllable:No

    Description:Whether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.

Advanced Parameters

  • primary_emissivity1The emissivity of the primary surface

    Default:1

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:The emissivity of the primary surface

  • secondary_emissivity1The emissivity of the secondary surface

    Default:1

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:The emissivity of the secondary surface

  • stefan_boltzmann5.67037e-08Stefan-Boltzmann constant

    Default:5.67037e-08

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:Stefan-Boltzmann constant

Gap Radiative Flux Parameters

  • prop_getter_suffixAn optional suffix parameter that can be appended to any attempt to retrieve/get material properties. The suffix will be prepended with a '_' character.

    C++ Type:MaterialPropertyName

    Unit:(no unit assumed)

    Controllable:No

    Description:An optional suffix parameter that can be appended to any attempt to retrieve/get material properties. The suffix will be prepended with a '_' character.

  • use_interpolated_stateFalseFor the old and older state use projected material properties interpolated at the quadrature points. To set up projection use the ProjectedStatefulMaterialStorageAction.

    Default:False

    C++ Type:bool

    Controllable:No

    Description:For the old and older state use projected material properties interpolated at the quadrature points. To set up projection use the ProjectedStatefulMaterialStorageAction.

Material Property Retrieval Parameters

Input Files

References

No citations exist within this document.