Electromagnetic Heating
The Electromagnetic Heating multiphysics coupling () adds the source term Qe (SI unit: W/m3) to account for resistive heating in the heat equation:
(7-1)
The resistive heating (ohmic heating) due to the electric current is
where J is the current density (SI unit: A/m2), and E is the electric field strength (SI unit: V/m).
In addition, it maps the electromagnetic surface losses as a heat source on the boundary (SI unit: W/m2) in the heat transfer part of the model.
Settings
The Label is the default multiphysics coupling name.
The Name is used primarily as a scope prefix for variables defined by the coupling node. Refer to such variables in expressions using the pattern <name>.<variable_name>. In order to distinguish between variables belonging to different coupling nodes or physics interfaces, the name string must be unique. Only letters, numbers, and underscores (_) are permitted in the Name field. The first character must be a letter.
The default Name (for the first multiphysics coupling in the model) is emh1.
Domain Selection
When nodes are added from the context menu, you can select Manual (the default) from the Selection list to choose specific domains to define the electromagnetic heat source or select All domains as needed.
When Electromagnetic Heating is added as an effect of adding a Joule Heating or Joule Heating and Thermal Expansion interface, the selection is the same as for the participating interfaces.
Only domains that are active in the physics interfaces selected in the Coupled Interfaces section can be selected.
Boundary Selection
When nodes are added from the context menu, you can select Manual (the default) from the Selection list to choose specific boundaries to define the electromagnetic boundary heat source or select All boundaries as needed.
When Electromagnetic Heating is added as an effect of adding a Joule Heating or Joule Heating and Thermal Expansion interface, the selection is the same as the exterior and interior boundaries of the Domain Selection of the participating physics interfaces.
Only boundaries that are active in the physics interfaces selected in the Coupled Interfaces section can be selected.
Coupled Interfaces
This section defines the physics involved in the multiphysics coupling. By default, the applicable physics interface is selected in the Electromagnetic list to apply the Heat transfer to its physics interface to establish the coupling.
The default values depend on how the coupling node is created.
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If it is added from the Physics ribbon (Windows users), Physics contextual toolbar (macOS and Linux users), or context menu (all users), then the first physics interface of each type in the component is selected as the default.
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If it is added automatically when a multiphysics interface is selected in the Model Wizard or Add Physics window, then the two participating physics interfaces are selected.
You can also select None from either list to uncouple the Electromagnetic Heating node from a physics interface. If the physics interface is removed from the Model Builder (for example, Heat Transfer in Solids is deleted), then the Heat transfer list defaults to None as there is nothing to couple to.
Click the Go to Source button () to move to the main physics interface node for the selected physics interface.
If a physics interface is deleted and then added to the model again, then in order to reestablish the coupling, you need to choose the physics interface again from the Heat transfer or Electromagnetic lists. This is applicable to all multiphysics coupling nodes that would normally default to the once present physics interface. See Multiphysics Modeling Workflow.