17.6.2.21. Heat Flux

Heat Flux is available for 3D simulations and 2D simulations for Plane Stress and Axisymmetric behaviors only. For the required geometry settings for Plane Stress and Axisymmetric behaviors, see the 2D Analyses section of the Help.

The Heat Flux boundary condition applies a uniform heat flux to the selected geometry. A positive heat flux acts into a face or edge, adding energy to a body. Heat flux is defined as energy per unit time per unit area. If you select multiple faces or edges when defining the heat flux, the same value gets applied to all selected faces.

This page includes the following sections:

Analysis Types

Heat Flux is available for the following analysis types:
Dimensional Types

The supported dimensional types for the Heat Flux boundary condition include:

  • 3D Simulation: Supported for Body and Face selections only.

  • 2D Simulation: Supported for Edge selections only.

Geometry Types

The supported geometry types for the Heat Flux boundary condition include:

  • Solid

  • Surface/Shell

Topology Selection Options

The supported topology selection options for Heat Flux include:

  • Body: Supported for 3D only.

  • Face

  • Edge: Supported for 2D only.

  • Element Face

Magnitude Options

The supported Magnitude options for Heat Flux include the following:

  • Constant

  • Tabular (Time Varying)

  • Function (Time Varying): Not supported for LS-DYNA analyses.

Applying a Heat Flux Boundary Condition

To apply a Heat Flux:

  1. On the Environment Context tab, click Heat>Heat Flux. Alternatively, right-click the Environment tree object or in the Geometry window and select Insert>Heat Flux.

  2. Define the Scoping Method as either Geometry Selection or Named Selection and then specify the geometry.

  3. Enter a Magnitude for the Heat Flux.

Details Pane Properties

The selections available in the Details pane are described below.

CategoryProperty/Options/Description
Scope

Scoping Method: Options include:

  • Geometry Selection: Default setting, indicating that the boundary condition is applied to a geometry or geometries, which are chosen using a graphical selection tool.

    • Geometry: Visible when the Scoping Method is set to Geometry Selection. Displays the type of geometry (Body, Face, etc.) and the number of geometric entities (for example: 1 Body, 2 Edges) to which the boundary has been applied using the selection tools.

  • Named Selection: Indicates that the geometry selection is defined by a Named Selection.

    • Named Selection: Visible when the Scoping Method is set to Named Selection. This field provides a drop-down list of available user-defined Named Selections.

Definition

Type: Read-only field that displays boundary condition type - Heat Flux.

Magnitude: Heat flux density value.

Suppressed: Include (No - default) or exclude (Yes) the boundary condition.

Mechanical APDL References and Notes

The following Mechanical APDL commands, element types, and considerations are applicable for this boundary condition.

  • Heat Flux is applied using the SF command and SURF152 (3D thermal analyses) and SURF151 (2D thermal analyses) element types.

  • Heat Flux (constant, tabular, and function) is always represented as a table in the input file.

LS-DYNA References and Notes

The following LS-DYNA keywords and considerations are applicable for this boundary condition.

API Reference

For specific scripting information, see the Heat Flux section of the ACT API Reference Guide.