- 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>
Controllable:No
Description:The name of the temperature variable
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
[radiation]
type = GapFluxModelRadiation
temperature = temp
boundary = 100
primary_emissivity = 1.0
secondary_emissivity = 1.0
use_displaced_mesh = true
[]
GapFluxModelRadiation must be used in conjunction with the modular gap conductance constraint as shown below:
[ced]
type = ModularGapConductanceConstraint
variable = lm
secondary_variable = temp
use_displaced_mesh = true
primary_boundary = 100
primary_subdomain = 10000
secondary_boundary = 101
secondary_subdomain = 10001
gap_flux_models = radiation
[]
Input Parameters
- primary_emissivity1The emissivity of the primary surface
Default:1
C++ Type:double
Controllable:No
Description:The emissivity of the primary surface
- 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
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.
- secondary_emissivity1The emissivity of the secondary surface
Default:1
C++ Type:double
Controllable:No
Description:The emissivity of the secondary surface
- stefan_boltzmann5.67037e-08Stefan-Boltzmann constant
Default:5.67037e-08
C++ Type:double
Controllable:No
Description:Stefan-Boltzmann constant
Optional 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).
- 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.
- 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
- 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.