Selecting the Physics Models and Materials

Simcenter STAR-CCM+ provides several physics models for computing the magnetic vector potential. The following steps include guidelines for choosing the model that is appropriate to your analysis.

Simcenter STAR-CCM+ offers both a finite element (FE) and a finite volume (FV) approach to solve for the magnetic vector potential. In general, the finite element (FE) approach is the preferred approach, particularly for domains with spatial variation in magnetic permeability or for electromagnetic force or torque calculations.

As the FE method imposes specific interface and mesh requirements, choose the discretization strategy before you prepare the required regions, interfaces, and mesh. For more information on the FE mesh and interface requirements, see Finite Element Magnetic Vector Potential Model Reference.

  1. Before you set up the physics continua, prepare the required geometry, regions, interfaces, and mesh, as appropriate to your analysis.
    For more information on these general operations, see 常规模拟过程.
  2. Create physics continua and assign them to the relevant regions.
  3. In each physics continuum, activate physics models as required. To model magnetic fields, include the following models:
    Group Box Physics Model
    Space
    • To solve for the magnetic vector potential in a 3D domain, activate the Three Dimensional model.
    • To solve for transverse-electric (TE) or transverse-magnetic (TM) modes in a 2D domain, activate either the Two-Dimensional or the Axisymmetric model.

      In the TE configuration, the magnetic field is normal to the 2D domain. The normal component of the magnetic vector potential, and of any external current density, is zero.

      In the TM configuration, the magnetic field lies in the plane of the 2D domain. The magnetic vector potential and the electric current density have only the vector component normal to the 2D domain.

      注The Axisymmetric model is only compatible with the FV models. When using the Axisymmetric model, make sure that you use an appropriate mesh resolution near the axis.
    Material Choose one of the material models based on requirements.

    The FE framework supports single-component or multi-component solids, and single-component gases. The FV framework also supports multi-component fluids.

    Optional Models Activate the Electromagnetism model.
    Electromagnetism
    • To solve for transverse-magnetic (TM) modes in a 2D domain, activate one of the following models:
      • Transverse Magnetic Potential (see 横向磁势模型参考):

        Solves for the transverse magnetic potential using the finite volume (FV) approach. (see 横向磁势模型参考).

      • Harmonic Balance FV Transverse Magnetic Potential model.

        Solves for the transverse magnetic potential in the frequency-domain using the finite volume (FV) approach. This solution technique is ideal for modeling fields with harmonic (sinusoidal) time dependence in linear materials. See 谐波平衡 Fv 横向磁势模型参考.

    • To solve for transverse-electric (TE) modes in a 2D domain, or for the magnetic vector potential in a 3D domain, activate one of the following models:
      • Finite Element Magnetic Vector Potential—suitable for all materials. This model has specific interface and mesh requirements. See Finite Element Magnetic Vector Potential Model Reference.

        For one-way coupled electromagnetic-stress analysis, where Simcenter STAR-CCM+ calculates the displacement of a solid in response to electromagnetic loads, activate this model together with the Solid Stress model. See Selecting Solid Stress Physics Models.

      • Harmonic Balance FE Magnetic Vector Potential—specific for fields with harmonic (sinusoidal) time dependence in linear materials. See Harmonic Balance FE Magnetic Vector Potential Model Reference.
      • Finite Volume Magnetic Vector Potential—only appropriate for magnetostatic MHD applications (such as plasma) with spatially invariant magnetic permeability. See 有限体积磁矢势模型参考. For materials with spatially varying permeability or for electromagnetic force and torque calculations, use the Finite Element Magnetic Vector Potential model.
      • Harmonic Balance FV Magnetic Vector Potential—specific for fields with harmonic (sinusoidal) time dependence in linear materials. Only appropriate for materials with spatially invariant magnetic permeability. This model automatically sets the magnetic permeability to the permeability of vacuum. See 谐波平衡 Fv 磁矢势模型参考.
    Time
    • When using harmonic balance models, Simcenter STAR-CCM+ calculates the magnetic potential in the frequency domain and, therefore, all time models are equivalent. In this case, choose between Steady and Implicit Unsteady based on the other physics that is solved in the continuum.

      By default, Simcenter STAR-CCM+ activates the Eddy Current Suppression model, which suppresses eddy currents in all regions associated with the continuum. You can always leave this model active, as it provides region settings for enabling eddy currents in specific regions.

    • When using the other magnetic potential models, Simcenter STAR-CCM+ calculates the magnetic potential in the time domain. In this case, choose between:
      • Steady—all quantities are time-independent. The steady solution does not account for transient effects such as eddy currents induced by time-varying magnetic fields.
      • Implicit Unsteady—quantities are time-dependent. For convenience, Simcenter STAR-CCM+ automatically activates the Eddy Current Suppression model. In conducting regions, where the effects of eddy currents can be important, you can deactivate the suppression using the region settings.

    For more information on the Eddy Current Suppression model, see Eddy Current Suppression Reference.

  4. The source of magnetic field is the electric current density J . You can either prescribe an electric current density, or calculate it in Simcenter STAR-CCM+ using the following models:
    • To account for J as induced by excitation coils, activate either the Excitation Coil model or the Finite Element Excitation Coil model. For instructions and guidelines, see 励磁线圈建模.
    • To account for J as induced by permanent magnets, activate the Permanent Magnet model. See 永磁建模.
    • To account for J as induced by differences in electric potential, activate one of the electrodynamic potential models. See 电流建模.
    • To calculate the magnetic nodal force, activate the Magnetic Nodal Force model. This model is only available when you activate the Finite Element Magnetic Vector Potential model. See 磁节点力模型参考.
  5. To model isotropic and anistropic solids in the same simulation, you can set up the physics continua in one of two ways:
    • Single physics continuum for both solid materials using the Multi-Part Solid model: in this case, you define the isotropic permeability as a scalar, and the anisotropic permeability as a tensor. You can visualizze the permeability of both solids in the same scene by plotting the Permeability (Symmetric Tensor) field function.
    • One physics continuum for each solid material: in this case, one continuum defines the isotropic solid and one continuum defines the anisotropic solid. As the permeability tensor is only defined for the anisotropic continuum, you can visualize the permeability using two distinct scenes (one for the Permeability field function in the isotropic region and one for the Permeability (Symmetric Tensor) field function in the anisotropic region).
  6. You can activate additional models from the Optional Models group box, based on analysis requirements.

    For example, you can model power losses in electric machines, Ohmic Heating, and the interaction between electrically conducting fluids (such as molten metals and plasma) and the magnetic field. For more information, see 损耗建模, 电阻加热建模, and 磁流体动力 (MHD) 建模.

    You can also model laminated steel materials by using the Laminated Steel model and defining the relevant material properties. For more information, see Laminated Steel Model Reference.

  7. For each continuum, select appropriate materials from the Simcenter STAR-CCM+ material library.
    You can either choose basic materials from the Standard material database, or you can select materials from the Electromagnetic material database. The Electromagnetic material database contains predefined materials from a variety of vendors and, depending on the material, can include data such as B-H curves and temperature-dependent quantities.
    For more information, see 常规模拟过程.
For the Finite Element Magnetic Vector Potential model, you can define the finite element order used in the simulation:
  1. Select the [physics continuum] > Models > Finite Element Magnetic Vector Potential node and set Element Order to the required value.
    The element order can range between 0 and 3, with 0 representing lowest order finite elements. For most simulations, you are recommended to use an order of 2. Higher-order elements are incompatible with the following:
    • Prism Elements.
    • Wedge Elements.
    • Insulating option for boundaries and interfaces—See Boundary Settings.
    • Mapped Contact Interfaces.
    For more information, see Element Order.
All magnetic vector potential models support direct interfaces (either internal or contact interfaces) with conformal mesh. Additionally, the Finite Element Magnetic Vector Potential model supports indirect mapped contact interfaces, which allow for non-conformal meshes.

In general, direct interfaces are preferred, as a non-conformal mesh can lead to a drop in the magnetic flux density and result in large errors when the mesh differences become large.

When you use mapped contact interfaces:

  1. Select the Interfaces > [Mapped Contact Interface] > Physics Values > Interpolation Stencil node and set Stencil Type to Imprint.