"Multiple Boundary Condition or Interference Assignments" error using Conjugate Heat Transfer Simulation

Project Support
1

Hello everyone,

I have been working on a Conjugate Heat Transfer simulation for a while and it appears ive got most issues fixed except for this one. When I go to simulate I get this error message regarding my inlet and outlet faces

Simulation Error - Feb 23
Simulation Error - Feb 231367×791 145 KB
.

A few notes for added information, I am trying to simulate the steady-state temperatures inside a modeled robot design. I added the control volume around the robot body because it is not air-tight and I couldn’t get an “inner region” created without it. The link to the project is here: https://www.simscale.com/workbench/?pid=2839096624495565266&mi=spec%3Abb44b9ea-edc1-4ab2-83f2-33afd67fcd37%2Cservice%3ASIMULATION%2Cstrategy%3A77

I know you cant have overlapping parts, which is what the error is saying but I specifically left a gap to try to remedy this issue with no luck. Looking forward to hearing any ideas on how to fix this if anyone has had this issue before. I have simplified my CAD significantly in order to make the simulation easier.

Edit: Extra info I forgot to mention, I was able to get a mesh created but it said the simulation physics were not valid and thus was not optimized.

thank you in advance!!

2

Hi!

The issue here is quite simple: you are defining both velocity AND pressure for the inlets and outlets. This is actually not necessary. Attempting to define both boundary conditions to the same faces will cause the system to be overconstrained, thus it’s not possible to run the project.

Basically, the following combinations will work:

  • Pressure inlet + velocity outlet
  • Velocity inlet + pressure outlet

So you can either delete the two in red, or the two in black:

image
image1484×769 78.9 KB

Cheers

1 Like
3

Hello,

Thank you very much, it allowed me to run the simulation after those changes! I was trying to model having fans at the inlet and outlet which is why I included both velocities but I guess that wouldn’t change the speed out the air leaving.

Thanks again!