TEAM 24 Validation Case

The TEAM 24 validation case belongs to electromagnetics. This test case aims to validate the following parameters:

• BH magnetic permeability curve
• Closed coils
• Forces and torques result control
• Coil current

SimScale’s simulation results were compared to measured data presented in TEAM Workshop Problem 24\(^1\).

Geometry

The geometry used in the TEAM 24 validation case is similar to a switched reluctance machine. The assembly contains 2 closed copper coils, a steel rotor, and a steel stator. For a total of 0.35 seconds of analysis, the torque on the rotor (around Z axis) and the current on the coils are analyzed.

An air domain is created around the assembly in order to run the simulation. The resulting geometry is the following:

Analysis Type and Mesh

Analysis Type: Electromagnetics

Model: Time-Transient Magnetostatics

Mesh and Element Types: The meshes from this validation case were created in SimScale with the Standard meshing algorithm.

Find below an overview of the meshes used in this validation study:

Mesh	Mesh Type	Nodes	Element Type
Coarse Mesh	Standard	357297	3D tetrahedral
Moderate Mesh	Standard	790589	3D tetrahedral
Fine Mesh	Standard	2350806	3D tetrahedral

Figure 3 shows how the finest mesh captures the surfaces of the assembly:

Simulation Setup

Material:

• Air: flow region
  • Material behavior: Soft magnetic
  • \((σ)\) Electric conductivity: 0 \(S/m\)
  • Magnetic permeability type: Constant
  • \((μ_r)\) Relative magnetic permeability: 1
  • Core losses: None
• Copper: both coils
  • Material behavior: Soft magnetic
  • \((σ)\) Electric conductivity: 5.7e7 \(S/m\)
  • Magnetic permeability type: Constant
  • \((μ_r)\) Relative magnetic permeability: 1
  • Core losses: None
• Steel: rotor and stator
  • Material behavior: Soft magnetic
  • \((σ)\) Electric conductivity: 4.54e6 \(S/m\)
  • Core losses: None
  • Magnetic permeability type: BH curve, available in Team Problem 24\(^1\), and for download below

Coils:

Two coils with the same setup are present in this validation case.

Since a quarter model is used, the setup involves an open coil with the following settings:

• Topology: Closed
• Coil type: Stranded
• Number of turns: 3500
• Wire diameter: 0.001 \(m\)
• Additional resistance: 0 ohms
• Excitation: Voltage
• \(U(t)\) Voltage: a time-dependent table definition with the curve below, which was sampled from the reference publication\(^1\).

Boundary Conditions:

All 6 external air volume faces receive a magnetic flux tangential boundary condition.

Reference Solution

The reference publication\(^1\) presents experimental data for torque on the rotor due to the coils, as well as the currents on the coil.

Result Comparison

A mesh sensitivity study was performed with a set of three meshes, focusing on the torques observed on the rotor. The figure below shows, for the last timestep, how the torque around the Z direction evolves as more nodes are added to the mesh:

The sensitivity study shows great stability between the moderate and fine meshes, despite the great increase in mesh density, indicating mesh-independent results.

Find below a comparison between the fine mesh results and experimental data\(^1\) for torques on the rotor around the Z-direction:

As previously discussed, the currents on the coils have also been compared against experimental data\(^1\):

The simulation results shows good agreement with trends that were measured for torques on the rotor and currents on the coils.

Last updated: August 11th, 2025