# GapHeatTransfer

Transfers heat across a gap between two surfaces dependant on the gap geometry specified.

## Description

GapHeatTransfer calculates the amount of heat transferred across unmeshed gaps between two different blocks.

The quadrature option is generally recommended for most models. With this option, heat flux is computed and applied as an integrated boundary condition at the quadrature points on both faces. Use of the quadrature options generally gives smoother results, although there can be small differences in the heat flux on the two surfaces.

It is also important to use the appropriate gap_geometry_type parameter (PLATE, CYLINDER, or SPHERE) for the model geometry.

Two-dimensional Cartesian geometries are not restricted to be in or parallel to the X-Y coordinate plane.

## Example Input syntax

[ThermalContact]
[./left_to_right]
slave = leftright
master = rightleft
variable = temp
type = GapHeatTransfer
[../]
[]


## Input Parameters

• variableThe name of the variable that this boundary condition applies to

C++ Type:NonlinearVariableName

Options:

Description:The name of the variable that this boundary condition applies to

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

C++ Type:std::vector

Options:

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

### Required Parameters

• gap_tempTemperature on the other side of the gap

C++ Type:std::vector

Options:

Description:Temperature on the other side of the gap

• disp_yThe y displacement

C++ Type:std::vector

Options:

Description:The y displacement

• gap_geometry_typeGap calculation type. Choices are: PLATE CYLINDER SPHERE

C++ Type:MooseEnum

Options:PLATE CYLINDER SPHERE

Description:Gap calculation type. Choices are: PLATE CYLINDER SPHERE

• disp_zThe z displacement

C++ Type:std::vector

Options:

Description:The z displacement

• min_gap1e-06A minimum gap size

Default:1e-06

C++ Type:double

Options:

Description:A minimum gap size

• disp_xThe x displacement

C++ Type:std::vector

Options:

Description:The x displacement

• warningsFalseWhether to output warning messages concerning nodes not being found

Default:False

C++ Type:bool

Options:

Description:Whether to output warning messages concerning nodes not being found

• appended_property_nameName appended to material properties to make them unique

C++ Type:std::string

Options:

Description:Name appended to material properties to make them unique

• max_gap1e+06A maximum gap size

Default:1e+06

C++ Type:double

Options:

Description:A maximum gap size

• quadratureFalseWhether or not to do Quadrature point based gap heat transfer. If this is true then gap_distance and gap_temp should NOT be provided (and will be ignored) however paired_boundary IS then required.

Default:False

C++ Type:bool

Options:

Description:Whether or not to do Quadrature point based gap heat transfer. If this is true then gap_distance and gap_temp should NOT be provided (and will be ignored) however paired_boundary IS then required.

• paired_boundaryThe boundary to be penetrated

C++ Type:BoundaryName

Options:

Description:The boundary to be penetrated

• sphere_originOrigin for sphere geometry

C++ Type:libMesh::VectorValue

Options:

Description:Origin for sphere geometry

• gap_distanceDistance across the gap

C++ Type:std::vector

Options:

Description:Distance across the gap

• cylinder_axis_point_1Start point for line defining cylindrical axis

C++ Type:libMesh::VectorValue

Options:

Description:Start point for line defining cylindrical axis

• cylinder_axis_point_2End point for line defining cylindrical axis

C++ Type:libMesh::VectorValue

Options:

Description:End point for line defining cylindrical axis

• orderFIRSTThe finite element order

Default:FIRST

C++ Type:MooseEnum

Options:CONSTANT FIRST SECOND THIRD FOURTH

Description:The finite element order

• displacementsThe displacements appropriate for the simulation geometry and coordinate system

C++ Type:std::vector

Options:

Description:The displacements appropriate for the simulation geometry and coordinate system

### Optional Parameters

• enableTrueSet the enabled status of the MooseObject.

Default:True

C++ Type:bool

Options:

Description:Set the enabled status of the MooseObject.

• save_inThe name of auxiliary variables to save this BC's residual contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)

C++ Type:std::vector

Options:

Description:The name of auxiliary variables to save this BC's residual contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)

• 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

Options:

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.

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

C++ Type:std::vector

Options:

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

• seed0The seed for the master random number generator

Default:0

C++ Type:unsigned int

Options:

Description:The seed for the master random number generator

• diag_save_inThe name of auxiliary variables to save this BC's diagonal jacobian contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)

C++ Type:std::vector

Options:

Description:The name of auxiliary variables to save this BC's diagonal jacobian contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)

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

Default:True

C++ Type:bool

Options:

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

• vector_tagsnontimeThe tag for the vectors this Kernel should fill

Default:nontime

C++ Type:MultiMooseEnum

Options:nontime time

Description:The tag for the vectors this Kernel should fill

• extra_vector_tagsThe extra tags for the vectors this Kernel should fill

C++ Type:std::vector

Options:

Description:The extra tags for the vectors this Kernel should fill

• matrix_tagssystemThe tag for the matrices this Kernel should fill

Default:system

C++ Type:MultiMooseEnum

Options:nontime system

Description:The tag for the matrices this Kernel should fill

• extra_matrix_tagsThe extra tags for the matrices this Kernel should fill

C++ Type:std::vector

Options:

Description:The extra tags for the matrices this Kernel should fill