Design parameters can often involve a maximum critical temperature that causes a part failure. If your design is part of a larger design or system it may be of interest to understand and control the heat flow. A thermal analysis calculates the conduction of energy across the geometry. To run a thermal analysis, the model material must have a conductance, and a temperature difference must exist for heat transfer to occur. Available thermal loads include:
Thermal analyses are steady-state heat transfer analyses used to determine the steady-state temperature distribution and heat flow. The thermal conductivity of the material must be known as well as the ambient temperature and heat transfer coefficients at convection or radiation load surfaces. Heat is always transferred in the direction of decreasing temperature. Heat can be transferred by 3 different methods: conduction through solids, convection through a fluid or gas, and radiation.
| Name | Heat transfer effect |
|---|---|
| Conduction | Heat flow within a solid body. |
| Convection | Heat in and out of a solid body into a fluid, such as air or water. Convection typically transports warmer fluid away from the surface and replaces it with cooler fluid. |
| Radiation | Heat in and out of separated objects, by electromagnetic waves, with or without a medium in between. |
When performing a thermal analysis on an assembly, it is important that you consider the resistance to heat flow that occurs along contact areas. For thermal analyses, an additional contact setting appears in the Edit Contact dialog:
By default, bonded contact provides perfect conductance of heat from one body to the other (zero resistance). To accurately represent resistance to the flow of heat across a contact interface, you must specify a suitable Thermal Conductance value. For example, heat does not conduct perfectly between a transistor and a heat sink, especially with an electrical insulator included between them. In operation, the transistor contact face is hotter that the heat sink contact face. This phenomenon is not reflected in your thermal results unless you specify a suitable Thermal Conductance value.
Thermal Conductance is inversely proportional to thermal resistance. The lower the conductance, the higher the resistance to the flow of heat. The greater the resistance to heat flow, the greater the temperature difference across the contact interface.
Contact types are limited to the following two choices for Thermal analyses:
However, all contact types are supported for Thermal Stress analyses.
This type of analysis requires: