Conjugate heat transfer and rotating zone

Hi everyone,

I have been playing around with the rotating zone concept to simulate the flow of air generated by a rotating spinneret in open and close environment. I have been obtaining nice results and I want to now add more complexity by simulating the conjugate heat transfer by heating the rotating object. I have simplified the geometry to get a hang of the problem but I can’t get to run the simulation.

A rotating cone is heated (38000 deg/s = 100 rps) by a power source (100W) in an open environment.
A simple cone for the solid object. The fluid volume is generated by cutting the cone out of a large cylinder. The MRF zone is also a cylinder encompassing the whole cone. Picture below
I work with FreeCAD and all the geometry was exported to .step format.
Advanced concepts:

  • The MRF is obviously the rotating zone
  • The fluid volume is set at constant inlet/outlet of pressure
  • The cone is heated at a constant power.

I want to compute the temperature/heat dissipation at the air-cone interface and study the cooling due to different rotation speeds.

The workspace can be found here:


  • The interfaces seems well detected, but when I add (and run the simulation) the wall boundary condition to the inner region of the fluid volume (as in more standard incompressible simulation) I get the error that the i have multiple assignments/interfaces to these faces.
  • If I remove the wall condition, I get the error that no material has been assigned to region 2. I don’t know what is region 2 and I cannot find a region not assigned apart from the MRF.
  • I also get the warning that some domains are not connected.


I have tried to mess around but I cannot figure out how to correct the setup. It may also be coming from the CAD model itself.

Any insights or suggestions?


Hi @jlengaigne!

Did you figure out the issue in the meantime, I saw that your run has been successful,at least the latest one.



Hi @jousefm,

Unfortunatly I have not yet succeed on the conjugate heat transfer. I was testing some tweaks in the CFD-incompressible model only.