GasMixture

Calculates the gas mixture in the void space of a fuel element.

note:Often Created by an Action

This object can be set up automatically by using the Thermal Contact LWR Action action.

Theory related to gap heat transfer can be found in Gap Plenum Models. See also Gas Gap Conductance.

When using the Thermal Contact LWR Action, you may output the gas mixture with output_gas_mixture = true. Be sure to have csv = true in the Outputs block.

The order of the gases in the CSV output file is He, Ne, Ar, Kr, Xe, H $var element = document.getElementById("moose-equation-f232d534-de42-4af6-85ee-6d306a5b0c25");katex.render("_2", element, {displayMode:false,throwOnError:false});$ , N $var element = document.getElementById("moose-equation-d7348ffe-4538-44cf-bd1d-5669e7508758");katex.render("_2", element, {displayMode:false,throwOnError:false});$ , O $var element = document.getElementById("moose-equation-51c80bac-1f8d-412a-96ff-d17e1599ee8b");katex.render("_2", element, {displayMode:false,throwOnError:false});$ , CO, CO $var element = document.getElementById("moose-equation-c9225898-3258-4d75-b64e-0e63c1b9e4fc");katex.render("_2", element, {displayMode:false,throwOnError:false});$ , and H $var element = document.getElementById("moose-equation-758541bc-83be-4240-9f8d-8a2f4d3fa78c");katex.render("_2", element, {displayMode:false,throwOnError:false});$ 0.

Varying Fill Gas Fractions

The initial_fractions parameter takes a vector of function names. The number of entries matches the number of entries in initial_gas_types. Any numeric entries are treated as constant functions. If any Parsed Functions are used, they may be a function of time but should not be a function of position. The sum of the values of the functions must be one at all times. By setting these functions carefully, the user can smoothly transition the fill gas from one composition to another.

It is assumed that if the fill gas is varying, any fission gases are swept out of the gap.

Options beginning with refab_ can also be used to change the gas mixture, but these occur at distinct points in time. If a refabrication step occurs, the values in initial_fractions are no longer used.

[ThermalContact<<<{"href": "../../syntax/Modules/HeatTransfer/ThermalContact/index.html"}>>>]
  [thermal_contact]
    type = GasGapHeatTransfer
    variable = temp
    primary = 3
    secondary = 2

    initial_moles = moles_initial
    initial_gas_types = 'He Ne Ar'
    initial_fractions = 'He Ne Ar'
    gas_released = 'zero'
    released_gas_types = 'He'
    released_fractions = '1.0'
    roughness_coef = 0.0
    emissivity_primary = 0.0
    emissivity_secondary = 0.0
    output_gas_mixture = true
  []
[]

Input Parameters

contains_complete_historyFalseSet this flag to indicate that the values in all vectors declared by this VPP represent a time history (e.g. with each invocation, new values are added and old values are never removed). This changes the output so that only a single file is output and updated with each invocation
Default:False
C++ Type:bool
Controllable:No
Description:Set this flag to indicate that the values in all vectors declared by this VPP represent a time history (e.g. with each invocation, new values are added and old values are never removed). This changes the output so that only a single file is output and updated with each invocation
gas_releasedThe postprocessor(s) that will give the gas released.
C++ Type:std::vector<PostprocessorName>
Unit:(no unit assumed)
Controllable:No
Description:The postprocessor(s) that will give the gas released.
initial_fractions1.0 Fractions of initial fill gas associated with initial_gas_types. These may be given as Function names. Fractions must sum to one.
Default:1.0
C++ Type:std::vector<FunctionName>
Unit:(no unit assumed)
Controllable:No
Description:Fractions of initial fill gas associated with initial_gas_types. These may be given as Function names. Fractions must sum to one.
initial_gas_typesHeInitial fill gas types: He Ne Ar Kr Xe H2 N2 O2 CO CO2 H2O
Default:He
C++ Type:MultiMooseEnum
Options:He, Ne, Ar, Kr, Xe, H2, N2, O2, CO, CO2, H2O
Controllable:No
Description:Initial fill gas types: He Ne Ar Kr Xe H2 N2 O2 CO CO2 H2O
initial_molesThe Postprocessor that will give the initial moles of gas.
C++ Type:PostprocessorName
Unit:(no unit assumed)
Controllable:No
Description:The Postprocessor that will give the initial moles of gas.
parallel_typeREPLICATEDSet how the data is represented within the VectorPostprocessor (VPP); 'distributed' indicates that data within the VPP is distributed and no auto communication is performed, this setting will result in parallel output within the CSV output; 'replicated' indicates that the data within the VPP is correct on processor 0, the data will automatically be broadcast to all processors unless the '_auto_broadcast' param is set to false within the validParams function.
Default:REPLICATED
C++ Type:MooseEnum
Options:DISTRIBUTED, REPLICATED
Controllable:No
Description:Set how the data is represented within the VectorPostprocessor (VPP); 'distributed' indicates that data within the VPP is distributed and no auto communication is performed, this setting will result in parallel output within the CSV output; 'replicated' indicates that the data within the VPP is correct on processor 0, the data will automatically be broadcast to all processors unless the '_auto_broadcast' param is set to false within the validParams function.
refab_fractionsFractions of refab gas associated with refab_gas_types.
C++ Type:std::vector<std::vector<double>>
Unit:(no unit assumed)
Controllable:No
Description:Fractions of refab gas associated with refab_gas_types.
refab_gas_typesRefab gas types: He Ne Ar Kr Xe H2 N2 O2 CO CO2 H2O
C++ Type:std::vector<std::vector<std::string>>
Controllable:No
Description:Refab gas types: He Ne Ar Kr Xe H2 N2 O2 CO CO2 H2O
refab_timeThe time at which the plenum pressure must be reinitialized due to fuel rod refabrication.
C++ Type:std::vector<double>
Unit:(no unit assumed)
Controllable:No
Description:The time at which the plenum pressure must be reinitialized due to fuel rod refabrication.
refab_typeThe type of refabrication. 0 for instantaneous reset of gas, 1 for reset with constant fraction until next refabrication.
C++ Type:std::vector<unsigned int>
Controllable:No
Description:The type of refabrication. 0 for instantaneous reset of gas, 1 for reset with constant fraction until next refabrication.
released_fractions0.153 0.847 Fractions of released gas associated with released_gas_types.
Default:0.153 0.847
C++ Type:std::vector<std::vector<double>>
Unit:(no unit assumed)
Controllable:No
Description:Fractions of released gas associated with released_gas_types.
released_gas_typesKr Xe Released gas types: He Ne Ar Kr Xe H2 N2 O2 CO CO2 H2O
Default:Kr Xe
C++ Type:std::vector<std::vector<std::string>>
Controllable:No
Description:Released gas types: He Ne Ar Kr Xe H2 N2 O2 CO CO2 H2O

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).
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.
outputsVector of output names where you would like to restrict the output of variables(s) associated with this object
C++ Type:std::vector<OutputName>
Controllable:No
Description:Vector of output names where you would like to restrict the output of variables(s) associated with this object
use_displaced_meshFalseWhether 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:False
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

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

References

No citations exist within this document.

(test/tests/gap_heat_transfer_mixedgas/varying_gas.i)

#
# 1-D Gap Heat Transfer with multple gas species in gap
#
# This test exercises the abiity to vary the gas in the gap.  This can be most
#  easily seen by looking at the Postprocessors Helium, Neon, and Argon.
#

[GlobalParams]
  order = FIRST
  family = LAGRANGE
  displacements = 'disp_x disp_y disp_z'
[]

[Mesh]
  use_displaced_mesh = false
  [mesh]
    type = FileMeshGenerator
    file = gap_heat_transfer_mixedgas.e
  []
[]

[Functions]

  [temp]
    type = PiecewiseLinear
    x = '0   1'
    y = '100 200'
  []
  [Ne]
    type = ParsedFunction
    expression = 'if(t>1,0,0.25*(1+cos(pi*t)))'
  []
  [Ar]
    type = ParsedFunction
    expression = 'if(t>1,0,0.25*(1-cos(2*pi*t)))'
  []
  [He]
    type = ParsedFunction
    symbol_names = 'total Ne Ar'
    symbol_values = '1.0   Ne Ar'
    expression = 'total-(Ne+Ar)'
  []
[]

[Variables]
  [disp_x]
  []
  [disp_y]
  []
  [disp_z]
  []
  [temp]
    initial_condition = 100
  []
[]

[Physics/SolidMechanics/QuasiStatic]
  [blocks]
    add_variables = false
    strain = SMALL
  []
[]

[Kernels]
  [heat]
    type = HeatConduction
    variable = temp
  []
[]

[BCs]

  [fixed_x]
    type = DirichletBC
    boundary = '1 2 3 4'
    variable = disp_x
    value = 0
  []
  [fixed_y]
    type = DirichletBC
    boundary = '1 2 3 4'
    variable = disp_y
    value = 0
  []
  [fixed_z]
    type = DirichletBC
    boundary = '1 2 3 4'
    variable = disp_z
    value = 0
  []

  [PlenumPressure]
    [plenumPressure]
      boundary = 100
      initial_pressure = 1.039309e7
      temperature = temp_gas
      volume = internalVolume
      startup_time = 0.0
      output_initial_moles = moles_initial
    []
  []
  [temp_far_left]
    type = FunctionDirichletBC
    boundary = 1
    variable = temp
    function = temp
  []
  [temp_far_right]
    type = DirichletBC
    boundary = 4
    variable = temp
    value = 100
  []
[]

[ThermalContact]
  [thermal_contact]
    type = GasGapHeatTransfer
    variable = temp
    primary = 3
    secondary = 2

    initial_moles = moles_initial
    initial_gas_types = 'He Ne Ar'
    initial_fractions = 'He Ne Ar'
    gas_released = 'zero'
    released_gas_types = 'He'
    released_fractions = '1.0'
    roughness_coef = 0.0
    emissivity_primary = 0.0
    emissivity_secondary = 0.0
    output_gas_mixture = true
  []
[]

[Materials]
  [elasticity_tensor]
    type = ComputeIsotropicElasticityTensor
    block = '1 2'
    youngs_modulus = 1e6
    poissons_ratio = 0.3
  []
  [stress]
    type = ComputeLinearElasticStress
    block = '1 2'
  []
  [heat1]
    type = HeatConductionMaterial
    block = '1 2'
    specific_heat = 1.0
    thermal_conductivity = 1.0e8
  []
  [density]
    type = StrainAdjustedDensity
    block = '1 2'
    strain_free_density = 1
  []
[]

[Executioner]
  type = Transient

  solve_type = 'PJFNK'
  petsc_options_iname = '-ksp_gmres_restart -pc_type -pc_hypre_type -pc_hypre_boomeramg_max_iter'
  petsc_options_value = '201                hypre    boomeramg      4'
  line_search = 'none'

  use_pre_SMO_residual = true
  nl_rel_tol = 1e-6
  l_tol = 1e-3
  l_max_its = 500
  nl_max_its = 10

  start_time = 0.0
  dt = 1e-1
  dtmin = 1e-1
  end_time = 1.0
  num_steps = 5000

  [Predictor]
    type = SimplePredictor
    scale = 1.0
  []
[]

[Postprocessors]
  [temp_left]
    type = SideAverageValue
    boundary = 2
    variable = temp
    execute_on = 'initial timestep_end'
  []

  [temp_right]
    type = SideAverageValue
    boundary = 3
    variable = temp
    execute_on = 'initial timestep_end'
  []

  [flux_left]
    type = SideDiffusiveFluxIntegral
    variable = temp
    boundary = 2
    diffusivity = thermal_conductivity
  []

  [flux_right]
    type = SideDiffusiveFluxIntegral
    variable = temp
    boundary = 3
    diffusivity = thermal_conductivity
  []

  [internalVolume]
    type = InternalVolume
    boundary = 100
    component = 0
    execute_on = 'initial linear'
  []

  [temp_gas]
    type = SideAverageValue
    boundary = 100
    variable = temp
    execute_on = 'initial linear'
  []

  [Helium]
    type = FunctionValuePostprocessor
    function = He
    execute_on = 'initial timestep_begin'
  []
  [Neon]
    type = FunctionValuePostprocessor
    function = Ne
    execute_on = 'initial timestep_begin'
  []
  [Argon]
    type = FunctionValuePostprocessor
    function = Ar
    execute_on = 'initial timestep_begin'
  []

  [zero]
    type = ConstantPostprocessor
    value = 0
  []

[]

[Outputs]
  exodus = true
  csv = true
[]

Varying Fill Gas Fractions
Input Parameters
References