Issue with Thermal Simulation - Everything is the same temperature... sometimes?

[Anonymous]

So I'm trying to simulate the heat coming off of an LED and flowing into the various parts of the assembly.

When I have only 2 components (the stand on which the die sits on and the die itself) the simulation solves just fine. Same thing with any 2 other components, if I just have the die and the Silica gel encasing it, the thermal simulation seems fine.

The problem comes when I want to solve the simulation with the silica gel, the die, and the copper stand (not to mention there's also other components that are attached but I can't even get 3 separate components to solve)

When I hit solve and there's 3 components in the simulation, instead of solving correctly it says everything is 20C.

The really weird part is that it doesn't mess up when I use an applied temperature instead of a heat source or convection load (when I'm solving with 3 components). When I use a heat source the simulation basically acts like it's not there.

[innovatenate · Accepted solution]

Can you try using linear element order in the Simulation Settings and see if that helps? There's a known issue we are already aware that might cause this (referenced internally as ARRO-8124). The linear element order should serve as a work-around though. See the image below for more detail. 

Hint: You have to expand the advanced settings.

I hope that helps. Let me know if you have any questions.

[Anonymous]

Thanks, that worked. Also, it before I tried your solution I was able to get it to solve correctly only when I applied the heat sources on the edges instead of a face, and it also worked when I applied the heat source on a face that wasn't in contact with anything else. Changing it to Linear just fixed the problem outright without any other workarounds.