Create a Two-Resistor Component

If the considered problem deals with heat conduction and conjugate heat transfer in an electronic device containing small electronic packages (chips, etc.), you may use the ability of Flow Simulation to consider these packages as the two-resistor model, i.e. as a flat heat source with two specified thermal resistances to heat conduction from junction to case and from junction to board.

Restrictions and Limitations

This feature is available for the Electronics Cooling module users only.

Prerequisites

  • The available two-resistor characteristics are taken from the Engineering Database. Before creating an two-resistor component, go to the Engineering Database and define the two-resistor characteristics you want to use.

  • The Conduction option must be enabled on the Analysis Type tab of the General Settings or Wizard dialog.

Procedure

  1. Open the Two-Resistor Component  dialog:

    • On the ribbon, click Flow Simulation > Insert > Conditions > Two-Resistor Component.

    • On the toolbars, click Two-Resistor Component on the Flow Simulation Features toolbar.

    • In the menu, select Tools > Flow Simulation > Insert > Two-Resistor Component.

    • In the Flow Simulation Analysis tree, right-click the Two-Resistor Components item and select Insert Two-Resistor Component.

  2. Under Selection specify a component and its top surface to apply the two-resistor chip:

    • In the graphics area select at least one face of the component to specify the Top Face . The selected surface is considered as the “Case” node and the corresponding component will be automatically selected as Components to Apply the Two-Resistor .

    • Or in the flyout FeatureManager design tree select component(s) which you want to consider as Components to Apply the Two-Resistor . You can also select a component in the graphics area. Then select the at least one face of this component to specify the Top Face .

    The bottom surface, which is considered as the “Board” node, is defined automatically.

    Note:

    Note, that the top and bottom surfaces must be parallel to each other. Moreover, if you select several components, they must be connected.

    See “Selection List” for details.

  3. Under Component select two-resistor component from the Two-resistor Components list.

    If you want to add a new two-resistor component to the Engineering Database or edit an existing one, click Create/Edit to open the Engineering Database.

  4. Under Source specify the Heat Generation Rate .

    If you want to specify a time- or coordinate-dependent value, click Dependency  to the right of the parameter value input box (see “Dependency” for details).

  5. Under Solid Parameters, specify the Initial Solid Temperature .
  6. Under Displayed Temperature, select the node’s temperature which will be used to display results on the top of the two-resistor component.
  7. Under Goals you can select goals to associate with the two-resistor component.

    Those goals are created together with the two-resistor component and remain connected with the same geometry.

  8. When creating a new two-resistor component condition, in the Name Template box you can specify a template for its name.

    The default template is <EDB Name>, <Value> and <Number>, where <EDB Name> is the two-resistor component name in the Engineering Database, <Value> is the specified source and <Number> is the sequential number of the two-resistor component condition in the Flow Simulation Analysis tree. When the two-resistor component is created, <EDB Name> is replaced by the two-resistor component name (for instance, “CBGAFC_10X10mm”), <Value> is replaced by the specified Heat Generation Rate (for instance, “5 W”) and <Number> is replaced by the sequential number of the two-resistor component condition (for example, if the two-resistor component condition named “CBGAFC_10X10mm (5 W) 1” already exists, the new two-resistor component condition will be named “CBGAFC_10X10mm (5 W) 2” and so on). You can combine these standard elements in any order and add any appropriate characters to the template. To add a new standard element to the template, click the EDB Name  or Number  button.

  9. Click OK .

    -or-

    Click Keep Visible  before clicking OK  to keep the dialog open and define more two-resistor components.

Results

The new Two-Resistor Component item appears in the Flow Simulation Analysis tree.

To edit the definition of a Two-Resistor Component, in the Flow Simulation Analysis tree, double-click the Two-Resistor Component item, or right-click the item and select Edit Definition.

Also you can use a callout in the graphics area to edit definition of a Two-Resistor Component or a multiple condition definition to edit multiple items at once (see “Feature Callout” and “Editing Multiple Items at Once” for details).

Parent Topic: Two-Resistor Components