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
the
thermos designer 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.