SimScale CAE Forum

CHT for flow in insulated pipe with heat source

I am trying to model gas flowing in a metal pipe. The pipe has heat source and is insulated. I used hex-dominant parametric multi-region mesh. Defined boundary conditions for inlet, outlet and power applied to the outside of pipe. I tried to define or not define interface for pipe-insulation. The simulation crashes both times, the error is “Inconsistent definition of interface: this happens when one side of an interface is assigned to a boundary condition. You can avoid this by removing interface faces from boundary conditions.” It seems from the log that the problem is the insulation, once it starts to solve that volume, it crashes. How do you set it up correctly?


Adding the link to the project: (correct me if this isn’t the one you’re referrring to)

I think my colleague @sjoshi can have a look


Hello @bednarol,

I see that in your project you have two Simulations:

  1. heat transfer” - this Simulation has three Runs:
    1.1. “2kW power” - this Run was successful, and used a multi-region mesh with tetrahedral elements.
    1.2 “Run 4” - this Run failed with the Inconsistent definition of interface error. It used a multi-region mesh with hexahedral elements
    1.3 “Run 3” - same as above

  2. heat transfer 2” - this Simulation uses a mesh without the outer insulation. It has three runs which fail because of the machine running out of memory.

Now for some information:

  • For the Runs 1.2 and 1.3, the reason for the crash is that the mesh for the insulation region is incorrect. There is nothing wrong with the way you set up the mesh - we are investigating what causes the problem, and will get back to you shortly.
  • For the Run 1.1 (“2kW power”), you used a multi-region tetrahedral mesh - what was the reason for you to move to a hexahedral mesh?
  • For all Runs in Simulation 2 (“heat transfer 2”), the reason for the crash is that you have requested the writing of too many timesteps, which causes the machine to run out of storage space. To avoid this, please increase the write interval (which would thereby reduce the number of times you write the result). Since this is a steady-state simulation, the final timestep is what actually matters to us. So I would suggest that you set the Write interval (simulation run time) to the End time value.
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Thanks a lot for having a look. The reason why I switched from tet to hex is because I switched from convective to conjugated HT analysis and tet mesh does not seem to be a good choice. I got msg “The format of the mesh assigned to this simulation is not supported for the selected analysis type. Currently supported: OpenFOAM”. I am interested in CHT in runs 1.2 and 1.3. I created the second simulation just to prove that the second solid volume is causing the problem. I am not very interested in it.


Have you been able to figure out the meshing issue?

Thank you,


I’ll tag @sjoshi here to see if he’s been able to investigate the issue

Hello @bednarol,

Sorry for the delay in answering to you. It turns out that the cause for the incorrect mesh for runs 1.2 and 1.3 is already known, and a fix is in the pipeline.

I’ll ping you here once the problem is resolved.