Assign Resistance Properties
The Resistance Thermal Model dialog box contains the following general and thermal information for the selected boundary condition.
If needed, you can define Total Power as a spatial, or volumetric, profile using an expression and a 3D dataset. See Adding 3D Datasets for more information.
| Name |
The Name of the resistance appears in the Project Manager window and 3D Modeler window. |
| Thermal Specification | |
| Total Power | The Total Power specifies the total power dissipated by the resistance. |
| Flow Specification | |
| Fluid Material | The Fluid Material specifies the fluid for the resistance. By default, it is set to water. |
| Pressure Loss Type: Device/Approach | |
| Loss Coefficient | The Loss Coefficientis used to calculate the pressure loss across the resistance for each coordinate direction in the case of a linear, quadratic, or linear+quadratic velocity dependence relationship. |
| Free Area Ratio | The Free Area Ratio specifies the ratio of the open area to the total area of the resistance. |
| Pressure Loss Type: Power Law (dp/dl = C*vn) | |
| Coefficient, C | Coefficent, C is the coefficient used in the pressure drop calculation using the Power Law method. It is specified in SI units. |
| Exponent, n | Exponent, n is the exponent used in the pressure drop calculation using the Power Law method. It is specified in SI units. |
| Pressure Loss Type: Directional Loss Curve | |
| Edit X-, Y-, Z-dir Curve | Clicking these buttons displays the Edit Dataset dialog box for the associated coordinate direction. In the Edit Dataset dialog box, specify coordinates for velocity and pressure to create the pressure loss curve. See Adding Datasets for more information. |
| Laminar Flow | Enable Laminar Flow if the interior of the boundary condition is to be modeled as a laminar zone. This option is only enforced when a turbulent flow regime is selected in the Icepak Solve Setup dialog box. |
| Flow Direction |
For some problems in which the principal axes of the resistance are not aligned with the coordinate axes of the domain, the flow direction can be specified by enabling Flow Direction and specifying two direction vectors. The third direction, which is not explicitly defined, is normal to the plan defined by the two specified direction vectors. The second direction must be normal to the first. If you fail to specify two normal directions, the solver will ensure that they are normal by ignoring any component of the second direction that is in the first direction. You should therefore be certain that the first direction is correctly specified. Note: The Flow Direction is specified relative to the Global coordinate system.
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When using the Device/Approach pressure loss type, enter Loss Coefficient and Free Area Ratio values for Linear and/or Quadratic to specify linear, quadratic, or both. When specifying Linear, you must leave the Quadratic values as zero and vice versa.
Assigning a Resistance and Defining Thermal Properties
To assign a resistance boundary condition and define its properties:
- Press O to enable object-selection mode.
- Select and right-click a three-dimensional geometry component in the 3D Modeler window or the history tree.
- From the right-click menu, select Assign Thermal>Resistance.
- In the Resistance Thermal Model dialog box, enter a Name for the resistance.
- Under Thermal Specification, enter a value for Total Power.
- Under Flow Specification:
- Click Fluid Material to open the Select Definition dialog box and select a material.
- Select a Pressure Loss Type :
- Device/Approach: Enter values for Loss Coefficient and Free Area Ratio for the linear and quadratic directions.
- Power Law: Enter values for Coefficient, C and Exponent, n.
- Loss Curve: Create pressure loss curves for the required coordinate directions.
- If needed, enable Laminar Flow.
- If needed, enable Flow Direction and enter values for each coordinate direction.
- Click OK.
The boundary condition dialog has a Defaults tab, which contains information related to default settings for the boundary condition properties and the following buttons:
- Save Defaults saves the currently defined properties as the default for newly created boundary conditions.
- Revert to Standard Defaults sets the boundary condition properties to the saved default values.
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Click here for scripting information related to this feature. |