Creating Initial Temperatures
Initial temperatures represent the magnitude of temperature at the nodes throughout a body at the start of an analysis.
Initial temperatures can be applied in mechanical or heat transfer analysis cases.
A uniform initial temperature distribution can be defined, or the initial temperature data can be read from a particular step and increment in the results file or the output database file of a previous heat transfer analysis. You can also apply knowledgeware techniques to control the value of the initial temperature (for more information, see Applying Knowledgeware).
You can import temperature mapping data into an initial temperature definition from a Microsoft Excel spreadsheet (.xls*) or a text file (.txt). The imported temperature data must satisfy the following criteria:
The data must be arranged in four columns in the following order: X-coordinate, Y-coordinate, Z-coordinate, and temperature value.
The data must include a header row in which the dimensional data are provided in parentheses. Temperature data can be provided without dimensions. The following sample header row provides one example of proper header row syntax:
X(mm) Y(mm) Z(mm) Temperature()
The actual initial temperature values created from imported data will be the product of the dimensionless temperature values multiplied by the value you provide for the Magnitude of the initial temperature. For example, if your imported data specify a dimensionless value of 10 at the location (0, 0, 0) and you specify a value of 20Kdeg for the inital temperature object, the initial temperature at that location will be 200K for the analysis.
Initial temperatures can be applied to volume or part supports or to mesh parts.
This task shows you how to create an initial temperature on geometry.
Click the Initial Temperature icon
.The Initial Temperature dialog box appears, and an Initial Temperature object appears in the specification tree under the Fields objects set in the Initialization step.
You can change the identifier of the field by editing the Name field.
Select the geometry support (a volume, part, or mesh part). Any selectable geometry is highlighted when you pass the cursor over it. You can select several supports to apply the field to all supports simultaneously.
The Supports field is updated to reflect your selection.
Select the Distribution Type for the initial temperature:
Uniform: You will define a uniform initial temperature magnitude.
From job: The initial temperature data will be obtained from the results file of a previous heat transfer analysis.
If you selected the Uniform distribution type, enter a value for the initial temperature in the Magnitude field.
Right-click on the Magnitude field to add knowledgeware controls (for more information, see Applying Knowledgeware).
If you selected the Uniform distribution type, you can import and incorporate data mapping for initial temperature by performing the following steps from the Uniform Distribution options:
Toggle on Data mapping, then click the ... button.
The Data Mapping dialog box appears.
Click Browse, then select the spreadsheet or text file from which you want to import temperature data.
Once you select a file, you can display the imported data in tabular form in the Imported Table dialog box by clicking Show.
If desired, toggle on Display Bounding Box to display a three-dimensional box incorporating the minimum and maximum values from the imported table. The bounding box enables you to confirm that the support you select lies completely within the space dictated by the imported data; if a portion of the support is outside this box, an error will be returned during the analysis.
Click OK to close the Data Mapping dialog box.
If you selected the From job distribution type:
In the specification tree, select a previous heat transfer job from which the initial temperature data should be read.
In the Step and Increment fields, enter the step and increment number, respectively, of the heat transfer job from which the initial temperature data should be read.
Toggle off Interpolate Midside Nodes to use thermal data from the midside nodes in your model, where they are available.
Note: The output database location for the job from which the initial temperature is being read must be the same location where the new job will be run.
Click OK in the Initial Temperature dialog box.
Symbols representing the applied field are displayed on the geometry.