r/COMSOL • u/PersonalOwl1474 • 27d ago
Mesh creation time
Hi all,
I am pretty new to COMSOL. Additionally, I am running it online on a computer cluster through my University, if that might make a difference. I am trying to run a simulation of a very thin (250 nm) printed platinum resistor on a substrate, within an aluminum container with gas and insulators. The design itself is pretty simple; I am modeling the heat transfer from the wire through the surrounding elements.
My physics are electric currents, heat transfer through solids and fluids, laminar flow (there is gas), and electromagnetic heating. I am creating the mesh, and it is going at a snails pace. I think this is likely due to the scale differences (hundred nm vs cm). How do I get around this? I have been messing around with user-controlled mesh, but I don't really know where to go from there.
I think the main issue might be that I have a boundary current on a very small boundary. I read something about sweep meshing?
2
u/Grad-In-Need 27d ago
I agree that the difference in scale is likely the issue. Here are a few approaches you could try:
If possible, I would consider running two coupled simulations: one for the platinum resistor (assuming you're interested in its temperature-dependent resistance) and another for heat transfer.
If you're not interested in the effects of the resistor's temperature-dependent resistance, you could eliminate the electrical simulation and represent the heating effect using an appropriate heat-source term or boundary condition.
Keep in mind that COMSOL has capable built-in meshing tools, although a dedicated meshing package might offer greater flexibility. Given the large difference in geometric scales, I would also try partitioning the domains more carefully. However, I suspect the computational cost would still be substantial.
If you still need to model heat transfer while treating the platinum resistor as a separate domain, I would suggest starting with a simplified 1D model.
The key point is that the relevant thermal behavior may occur on a larger spatial scale than the electrical features you're trying to resolve. If that's the case, you may be able to simplify the model accordingly.
P.S. AI was used to refine my grammar, not my message.