There are two types of heat transfer analyses based on interest in time.
| Steady State Thermal Analysis |
In this type of analysis, we are only interested in the thermal conditions of the body when it reaches a state of thermal equilibrium. We are NOT interested in knowing the time it takes to reach this state. At thermal equilibrium, the thermal energy entering each point in the model is equal to the thermal energy leaving it. Generally, the only material property that is needed for steady state analysis is the thermal conductivity. |
| Transient Thermal Analysis |
In this type of analysis, we are interested in knowing the thermal status of the model as a function of time. A thermos designer, for example, knows that the temperature of the fluid inside will eventually be equal to the room temperature (steady state), but he or she is interested in finding out the temperature of the fluid as a function of time. In specifying material properties for transient thermal analysis, you need to specify thermal conductivity, density, and specific heat. In addition, you need to specify the initial temperatures, solution time, and time increment. |
For transient studies, you can associate heat flux and heat power conditions with a thermostat defined by a temperature range at a specified location. For each time step, the program turns the heat power or heat flux condition on or off based on the temperature at the thermostat location.