Assigning Hollow Block Properties

A hollow block is a block with a solid material assigned and the Solve Inside option disabled. Hollow blocks represent three-dimensional regions of the model for which only side characteristics are important. Icepak does not mesh or solve for temperature or flow within regions bounded by the sides of a hollow block. Hollow-block surfaces can be specified as adiabatic (impervious to heat flow) or as possessing a fixed, uniform temperature or heat flux.

The Block Thermal Model dialog box contains the following general and thermal information for the selected boundary condition.

Name	The Name of the boundary condition appears in the Project Manager window and 3D Modeler window.
Thermal Conditions: Fixed heat
Total Power	Total Power specifies the total power dissipated by the solid block. For steady-state simulations, if needed, select the check box and select Temp Dep or Joule Heating. For Temp Dep, click Edit to specify the temperature dependence of power. For transient simulations, select Temp Dep, Transient, or DTM. Alternatively, specify the power as Power Density. Transient allows you to specify power as a function of time. DTM (dynamic thermal modeling) allows you to specify a temperature-dependent power after each time step of a transient simulation.
Note: For more information on specifying transient power, see Specifying Parameters as a Function of Time. For more information on dynamic thermal modeling, see DTM - Thermostat for Source Control.
Heat flux	Heat flux specifies a constant uniform heat flux into or out of all block surfaces.
Thermal Conditions: Fixed temperature
Fixed Temperature	Fixed Temperature specifies a constant uniform temperature for all the block surfaces.
Thermal Conditions: Internal conditions
Internal Thermal Conditions	Internal Thermal Conditions specifies a Heat Transfer Coefficient and a reference Temperature for the internal volume of space inside the block.

Assigning a Hollow Block and Defining Thermal Properties

To assign a hollow block boundary condition and define its properties:

1. Press O to enable object-selection mode.
2. Select and right-click a three-dimensional geometry component in the 3D Modeler window or the history tree.
   Note:

   To assign a hollow block type, ensure that the material assigned is solid and the Solve Inside option is disabled.

3. From the right-click menu, select Assign Thermal>Block.
4. In the Block Thermal Model dialog box, enter a Name for the block.
5. Select a Thermal Conditions and enter the associated values:
• Fixed heat: Total Power or Heat flux. For steady-state simulations, if needed, select the check box and select Temp Dep or Joule Heating. For transient simulations, select Temp Dep, Transient, or DTM. For Temp Dep, click Edit to open the Temperature Dependent Variation dialog box and specify the Variation function and values.
• Fixed temperature: Fixed Temperature.
• Internal conditions: Heat Transfer Coefficient and a reference Temperature.
6. Click OK.