In this unit, we will perform a simple transient simulation using the HEAT solver to simulate
the time dependency of temperature in a glass thin-film covered with graphene.
The project file contains two materials, glass and graphene and two geometric objects, thin_film
Note that the length and thickness of both the thin_film and graphene objects are slightly
larger than the specifications.
This will cause the length and thickness of the simulation region to define the dimensions
of the simulated thin film and makes it easier to change their dimensions.
The material for "thin_film" is set to SiO2 and the material for the "graphene" object
is set to graphene.
The simulation region is set to be two-dimensional.
Since we want to see the time evolution of the temperature profile, the HEAT solver mode
has been set to "transient".
When using this mode, the transient tab in the HEAT solver properties window can be used
to setup the transient simulation.
For our simulation, set the minimum time step to 1us (1e9 fs), max time step to 10 us (1e10
fs) and both tolerance limits to 0.001.
There are two thermal boundary conditions (left and right) defined in the "Boundary
The "left" boundary condition sets the left edge of the thin film at a fixed temperature
of 300 K.
The "right" boundary condition is set to the transient mode and raises the temperature
on the right edge from 300 K to 400 K at t = 1 us and then keeps it constant at 400 K
up to 200 us.
The end time in the temperature table of the "right" boundary condition also sets the end
time for the transient simulation.
Lets run the simulation.
You will notice that during the simulation, the job manager window will show you the exact
times at which the simulation is being performed.
After running the simulation, right-click on the solver object and select "Visualize
> thermal" to view the temperature profile.
The thermal dataset has multiple results (or attributes) saved.
To view the temperature profile, select the "T" attribute from the list of attributes
in the visualizer.
The temperature profile will be a function of time which will be shown in the "parameter"
table below the image.
Select the "t" parameter and change the time using the slide on the right side of the table.
As can be seen from the temperature profile, the heat coming from the right edge spread
much quickly near the top of the glass film due the presence of the highly conductive
As the time passes, the bottom of the film 'catches up' and the temperature distribution
becomes even and linear throughout the film.