Thermal Contact

This syntax is used to model thermal contact between surfaces using a node-on-face approach.

Gap offset parameters

Gap offset can be provided to the current contact formulation via the PenetrationAux. It can be either secondary_gap_offset (gap offset from secondary side) or mapped_primary_gap_offset (gap offset from primary side but mapped to secondary side). Use of these gap offset parameters treats the surfaces as if they were virtually extended (positive offset value) or narrowed (negative offset value) by the specified amount, so that the surfaces are treated as if they are closer or further away than they actually are. There is no resistance to heat transfer within the material in this gap offset region.

Multiple contact pairs (node/face)

Users may need to set up thermal contact between multiple contact pairs. For that application, users can provide arrays of primary and secondary boundary names which will match consecutively to define thermal contact pairs. The same thermal contact-related input parameters will be applied to all contact pairs defined in the action input.

[ThermalContact]
  [thermal_contact]
    type = GapHeatTransfer
    variable = temperature
    primary = '101 201'
    secondary = '100 200'
    emissivity_primary = 0
    emissivity_secondary = 0
    gap_conductance = 1.0e9
  []
[]

(moose/modules/heat_transfer/test/tests/multiple_contact_pairs/multiple_contact_pairs.i)

[Mesh]
  file = 3blk.e
[]

[Functions]
  [temperature]
    type = PiecewiseLinear
    x = '0   1   2'
    y = '100 300 300'
  []
[]

[ThermalContact]
  [thermal_contact]
    type = GapHeatTransfer
    variable = temperature
    primary = '101 201'
    secondary = '100 200'
    emissivity_primary = 0
    emissivity_secondary = 0
    gap_conductance = 1.0e9
  []
[]

[Variables]
  [temperature]
    order = FIRST
    family = LAGRANGE
    initial_condition = 100
  []
[]

[AuxVariables]
  [gap_cond]
    order = CONSTANT
    family = MONOMIAL
  []
[]

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

[BCs]
  [temp_far_left]
    type = FunctionDirichletBC
    boundary = '101 201'
    variable = temperature
    function = temperature
  []
  [temp_far_right]
    type = DirichletBC
    boundary = 'left right'
    variable = temperature
    value = 100
  []
[]

[AuxKernels]
  [conductance]
    type = MaterialRealAux
    property = gap_conductance
    variable = gap_cond
    boundary = 100
  []
[]

[Materials]
  [heat1]
    type = HeatConductionMaterial
    block = '1 2 3'
    specific_heat = 1.0
    thermal_conductivity = 100000000.0
  []
  [density]
    type = GenericConstantMaterial
    block = '1 2 3'
    prop_names = 'density'
    prop_values = '1.0'
  []
[]

[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'
  nl_rel_tol = 1e-8
  l_tol = 1e-3
  l_max_its = 100

  dt = 1e-1
  end_time = 1.0
[]

[Postprocessors]
  [temp_left]
    type = SideAverageValue
    boundary = 100
    variable = temperature
    execute_on = 'initial timestep_end'
  []

  [temp_right]
    type = SideAverageValue
    boundary = 200
    variable = temperature
    execute_on = 'initial timestep_end'
  []

  [flux_left]
    type = SideDiffusiveFluxIntegral
    variable = temperature
    boundary = 100
    diffusivity = thermal_conductivity
    execute_on = 'initial timestep_end'
  []

  [flux_right]
    type = SideDiffusiveFluxIntegral
    variable = temperature
    boundary = 200
    diffusivity = thermal_conductivity
    execute_on = 'initial timestep_end'
  []
[]

[Outputs]
  exodus = false
  csv = true
[]