Sources and Monitors in Ansys Lumerical HEAT — Lesson 6


There are two types of heat sources — Import and Uniform. They can be added to the simulation by clicking on the corresponding buttons in the Sources section under the HEAT tab. Once added they will appear as children of the Heat solver object in the Objects Tree.

1. Uniform heat: Allows you to define a region of uniform heat generation.


    • DIRECTLY DEFINED: The heat source can be 2D or 3D when defined directly using the x, y, z positions and spans of the source. Only 3D sources are allowed in 3D HEAT simulations while 2D simulations accept both 2D and 3D sources. If a 3D source is used in a 2D simulation, then the input power per unit length in W/m is calculated using the length of the 3D source in the third dimension and is applied to the simulation.
    • VOLUME: The source region can also be defined using reference geometries. For more information about reference geometries, please refer to the corresponding unit in this course.

Source parameters:

    • EQUIVALENT LENGTH (µm): Defines the length of the source in the third dimension (only applicable to 2D sources). In 2D simulations, as mentioned above, the input power for the simulation has units of W/m and is calculated by dividing the "total power" value (W) with the length in the third dimension defined by this parameter.
    • USE SOLVER NORM LENGTH: Only applicable to 2D sources. Enabling this option overrides the value of the "equivalent length" of the source with the "norm length" of the solver region so that the heat source and the simulation region have the same length in the third dimension.
    • TOTAL POWER (W): This is the total power injected over the volume of the source in units of Watts.

2. Import heat: Allows the import of a user-defined heat source.

Geometry tab:

The dimension of the imported data defines the geometry of the Import Heat source. Once the data is imported, the x, y, and z span of the source cannot be edited. However, the x, y, and z values can be used to shift the imported data to align with the desired region if necessary (setting the x, y, z values to 0,0,0 means there is no additional shift). You also have the option of applying the imported data to a specific domain using the reference geometries. In this case, only the parts of the imported data that overlap with the selected reference geometry are included in the simulation.

Data tab:

This tab is used to import the heat source data. The file must be in Matlab data format (.mat) and can contain a rectangular or unstructured (finite-element) dataset. Once the file is loaded, the available datasets can be viewed, and the appropriate dataset and attribute (data) can be selected. The unit for the imported data should be in W/m3. The scale factor option can be used to increase or decrease the amount of source heat power by a multiplying factor for calibration purposes. A value of 1 for the scale factor means that the original power values in the imported data will be used.


There are two types of monitors available in the HEAT solver: power flow and temperature.

1. Power flow: Records the total heat flux through a line, area or volume of the simulation region. The data has units of W/m in 2D and W in 3D.

General Tab:

    • MONITOR TYPE: The monitor geometry can be chosen. It can be a line in any direction, a plane normal to any of the axis or a 3D monitor.
    • RECORD TEMPERATURE: If enabled, the monitor records the temperature profile as well.

Geometry Tab:

This tab is used to define the x, y, and z positions and spans of the monitor.

2. Temperature: Records the temperature profile within the monitor space. The unit of the recorded data is Kelvins (K).

General tab:

    • MONITOR TYPE: The monitor geometry can be chosen. It can be a line in any direction, a plane normal to any of the axes or a 3D monitor.
    • o SAVE DATA: If enabled, it saves the data to a .mat file. The user needs to specify a filename and location.

Geometry tab:

This tab is used to define the x, y, and z positions and spans of the monitor.