Thermostat
For transient thermal studies, all heat power and heat flux assignments
can be controlled by a thermostat mechanism defined by a desirable temperature
range at a vertex. For each solution step, the status of the heat power
or flux condition (on/off) is decided based on the temperature at the
specified vertex in the previous step. You can use multiple thermostats
in a study.
If the value of the heat power or heat flux is positive, the device
acts as a heater that is turned on during the next solution step if the
current temperature of the sensor (vertex) is lower than the highest desired
temperature. Otherwise, the heating condition is turned off.
If the value of the heat power or heat flux condition is negative, the
device acts as a cooler that is turned on during the next solution step
if the current temperature of the sensor (vertex) is higher than the lowest
desired temperature. Otherwise, the cooling condition is turned off.
If the thermostat is working properly, the graph of temperature versus
time at the thermostat location should oscillate as shown in the figure
provided that adequate solution time is used. If the overshoot temperature
on one or both sides of the bounds is large, modify the properties of
the study to use a smaller time step and re-run the study.
If the temperature at the thermostat location converges to a temperature
outside or inside the desired range (as in curves 1 and 2), the specified
thermostat does not play a role in controlling the heat source. Change
the heat source, other thermal loads or restraints, material properties,
or the location of the thermostat.
If the temperature at the thermostat location approaches one side of
the temperature bounds with a slope without crossing it (as in curves
3 and 4), increase the solution time and rerun the study.
To define heat
flux with a thermostat
To
define heat power with a thermostat