Modeling Multiple Fans and Blowers in a Single Interface

With per-contact values you can model any number of fans or blowers, with different fan curves, in a single parts-based interface.

Although it is possible to specify per-contact values for fan curve polynomials and fan curve tables, there are other parameters associated with fans/blowers that currently do not allow per-contact values (fan swirl, fan curve temperature scaling, and blower heat generation rate).

Since fan swirl does not allow parts-based specification, interfaces that use per-contact values for fan curve polynomials and fan curve tables cannot have swirl enabled — doing so leads to incorrect results. Fan swirl allows the specification of a coordinate system to identify the fan-axis. If there are multiple contacts in an interface, each representing an individual fan, each fan will have a different axis. In the absence of parts-based support for fan swirl, the same coordinate system will be use for all fans leading to wrong computation of swirl.

To model multiple fan curves under a single interface:
  1. Activate per-contact values:
    1. Select the parts-based fan interface and set Allow Per-Contact Values to True.

      A Contact Subgrouping node is added to the fan interface.

  2. Create subgroups for each individual fan curve that you want to model:
    1. Expand the Contact Subgroupings > Subgrouping 1 node.

      By default, all part contacts are placed in the Subgroup 1 subgroup.

    2. To create a new contact subgroup, right-click Subgrouping 1 and select New.

      It is good practise to give each subgroup an appropriate name.

    3. Select the subgroup node and click next to Objects.
    4. In the Objects dialog, select the part contact that corresponds to the fan curve you want to model.
    5. Repeat these steps for each fan curve.
  3. If required, create new contact subgroupings to help manage subgroups:
    1. Right-click the Contact Subgroupings node and select New.
  4. Set up the fan curves:
    1. Select the [Fan_Interface] > Physics Values > Fan Curve Polynomial / Fan Curve Table node and set Specify by Part Subgroup to True.

      The By Contact Subgroup node appears under the Fan Curve Polynomial / Fan Curve Table node. This node contains all the subgroups.

      By default, the values from the interface Fan Curve Polynomial / Fan Curve Table node are copied to the Fan Curve Polynomial / Fan Curve Table subgroup nodes. If you want a different fan curve for any subgroup, you can expand and modify the corresponding Fan Curve Polynomial / Fan Curve Table subgroup node. See Specifying the Fan Performance Curve Polynomial.

    2. Repeat these steps for the remaining fan curves.

      If you want to model multiple fans that use the same fan curve, you are advised to create separate subgroups for each.