Setting Up Physics for Air and Core

In the simulation that this tutorial presents, only the electromagnetic behavior in response to the induced current is of interest. No fluid or thermal effects are considered. For this reason, a simplified approach is possible when defining the physics for the air and core regions.

By using the multi-part solid framework, one continuum is sufficient for defining the physics in the air and core regions. The electromagnetic properties for both air and the steel core can be defined in one continuum.

To define the physics for air and the core:

  1. Rename the Continua > Physics 1 node to Air and Core Physics.
  2. Right-click the Air and Core Physics node and click Select Models.
  3. First, remove the Two Dimensional model from within Enabled Models, then select the following models:
    Group box Physics Model
    Space Axisymmetric
    Time Implicit Unsteady
    Material Multi-Component Solid
    Multi-Component Solid Multi-Part Solid
    Optional Models Electromagnetism
    Enabled Models Gradients (selected automatically)
    Electromagnetism Transverse Magnetic Potential
    Optional Models Eddy Current Suppression (selected automatically)
    As you are only interested in the transverse magnetic potential, and not in the flow solution, you can model air as a solid. This modeling approach allows you to model the air and core components with a single region and physics continuum, using the Multi-Component Solid model.
    Alternatively, you could model the air and core parts using separate continua and regions. With this approach, you would model air as a fluid without selecting a flow model and, therefore, with computing the flow solution.
  4. To specify two materials within this continuum:
    1. Within the Air and Core Physics > Models node, expand the Multi-Part Solid node.
    2. Right-click the Solids node and choose Select Mixture Components....
    3. In the Select Mixture Components dialog, expand the Material Databases > Electromagnetic > Commonly Used Materials node.
    4. Select AIR (AIR) and CR10: Cold rolled 1010 steel (CR10: Cold rolled 1010 steel).
    5. Click Apply then Close.
  5. To set the respective properties of each material:
    1. Edit the Air and Core Physics > Models > Multi-Part Solid node, click Expand/Contract Tree, and set the following properties:
      Node Property Setting
      AIR
      Material Properties
      Electrical Conductivity > Constant Value 0.0 S/m
      Magnetic Permeability > Constant Value 1.25663753E-6 H/m
      As you are using the eddy current suppression model for the core, the electrical conductivity of CR10 has no effect on the solution. You model the magnetic permeability of the CR10 steel core using a B-H curve. For CR10 steel, Simcenter STAR-CCM+ automatically uses the predefined B-H curve defined within the Electromagnetic material database.
  6. To assign the relevant solid materials:
    1. Expand the Regions > Air and Core > Physics Values > Material Part Groups node.
    2. Select Material Part Groups > AIR and set Parts to Air and Air 2.
    3. Select the CR10: Cold rolled 1010 steel node and set Parts to core.
As this case is axisymmetric, the lower boundary of the air domain must be defined as an axis.
  1. To set the axis boundary, select the Regions > Air and Core > Boundaries > Air 2.alpha=30° node and set Type to Axis.
The simulation requires contact interfaces. Depending on the materials that you select for each interface, Simcenter STAR-CCM+ uses either an average diffusion coefficient or jumping diffusion coefficient for the correct computation of the fluxes at the interfaces.
  1. Multi-select the Interfaces > Air/coil1, Air/coil2, and Air/core nodes and set Type to Contact Interface.
  2. Save the simulation.