What Does an Initial Temperature Do?
- An initial temperature can be applied to selected nodes, surfaces, or parts in a model. If multiple nodes are selected, each node will have the temperature value applied to it. A surface initial temperature applies the temperature to each node on the surface. A part initial temperature applies the temperature to each node in the part.
- A nodal initial temperature specifies the temperature of the node at the beginning of the analysis (time = 0).
- In a transient heat transfer analysis, this specifies the starting temperature; the calculated temperature will change over time due to the heat loads applied to the model.
- In a steady state heat transfer analysis, the initial temperature (at time 0) has no affect unless the model contains some type of nonlinear temperature effect (temperature-dependent material properties, radiation, temperature-dependent convection, and so on). In this case, setting the starting temperature may help speed the convergence, but it will not affect the steady state solution.
- If no initial temperature is applied to a node, that node will start the analysis with the temperature defined in the Default nodal temperature field in the Options tab of the Analysis Parameters dialog.
Apply Initial Temperatures
If you have nodes, surfaces, or parts selected, you can right-click in the display area and select the Add pull-out menu. Select the Nodal Initial Temperatures or Surface Initial Temperatures or Part Initial Temperatures command, respectively. This command can also be accessed via the ribbon (Setup 
Thermal Loads Initial Temperature).
Specify the magnitude of the initial temperature (temperature at time = 0) that will be applied to each selected object in the Magnitude field.
Note: If different temperatures are applied to the same node, the last temperature will be used for the node. For example, if parts 1 and 2 are bonded together, and if part 1 is assigned a temperature of 100 degrees, then part 2 is assigned a temperature of 75 degrees, the nodes in common will have an initial temperature of 75 degrees.
Tip: Initial temperatures can also be imported from text files, or for transient heat transfer, from other models. See the pages, Setting Up and Performing the Analysis: General Information (Common to Multiple Analysis Types): Loads and Constraints: Loads from File and Setting Up and Performing the Analysis: Thermal: Analysis Parameters: Transient Heat Transfer, respectively.