Home / Examples / Coupled Analysis / Magnetic-Thermal Analysis [Gauss/Watt] / Example 2: IH Cooking Heater

Example 2: IH Cooking Heater

General

This is an example of the magnetic-thermal coupled analysis.
The model is a coil on the frying pan. AC current is applied to the coil to induce a current, resulting in a joule loss.
The resultant joule loss is solved in the magnetic analysis. The heating caused by the joule loss is solved in the thermal analysis.
The vectors of the magnetic field and the temperature distribution by the heating are viewed.
Unless specified in the list below, the default conditions will be applied.

Results will vary depending on Femtet version and the PC environment.

Analysis Space

Item	Settings
Analysis Space	3D
Model Unit	mm

Analysis Conditions

Item	Settings
Solver	Magnetic Analysis [Gauss] Thermal Analysis [Watt]
Analysis Type	Magnetic Analysis: Harmonic Analysis Thermal Analysis: Steady-state Analysis
Options	N/A

The frequency of the AC current is set to 10 [kHz].

Tab

Setting Item

Settings

Harmonic analysis

Frequency

Minimum: 10×103 [Hz]

Maximum: 10x103 [Hz]

Sweep Type

Linear Step by Division Number: Division 0

Set the Mesh Tab as follows.

Select [Apply the surface impedance boundary] for faster calculation.

[Apply the surface impedance boundary] is selectable if [No] is selected for Induced Current on the [Current] tab.

See [Frequency-Dependent Meshing] of [Mesh Tab].

Tab

Setting Item

Settings

Mesh

Meshing Setup

Automatically set the general mesh size: Deselect

General Mesh size: 20[mm]

Frequency-Dependent Meshing

Reference Frequency: 10×103 [Hz]

Surface Treatment for Conductors: Apply the surface impedance boundary

Model

Solid bodies of a frying pan (Metal) and a coil (Coil) are defined.

The automatically created ambient air is analyzed only in the magnetic analysis, not in the thermal analysis.

Body Attributes and Materials

Finer meshes are set on the area where the magnetic field changes drastically.

Body Number/Type	Body Attribute Name	Material Name
1/Solid	Coil1	008_Cu *
3/Solid	Coil2	008_Cu *
11/Solid	METAL	METAL
10/Solid	Handle	Wood

* Available from the material DB

The material properties are set up as follows:

Material Name	Tab	Properties
Wood	Thermal Conductivity	Thermal Conductivity: 0.5 [W/m/deg]
METAL	Permeability	Relative Permeability: 5x103
	Conductivity	Conductivity Type: Conductor Conductivity: 1x107
	Thermal Conductivity	Thermal Conductivity: 80

Body attribute is set up as follows to apply current to the loop coil.

The analysis domain is the magnetic analysis only as Coil is not used in the thermal analysis.

Body Attribute Name

Tab

Settings

Coil

Current

Waveform: AC

Current: 10 [A]

Turns: 20 [Turns]

Induced Current: Deselect

Direction: Loop Coil/Magnetic Field Direction

Direction Vector of Magnetic Field: X=0, Y=0, Z=1

Analysis Domain

For use in magnetic analysis

Boundary Conditions

[Natural Convection (Automatic Coefficient Calculation)] is set with the outer boundary condition (in the thermal analysis, the outer boundary condition is surrounding the frying pan).

Boundary Condition Name/Topology

Tab

Boundary Condition Type

Settings

Outer Boundary Condition *

Thermal

Heat Transfer: Convection

Natural Convection (Automatic Coefficient Calculation)

Ambient Temperature: 25 [deg]

To set Outer Boundary Condition, go to the [Model] tab