Verification against ISO 10211:2017 thermal test cases

Victor

Here are 4 simple thermal conduction test cases which confirm that Mecway's solution agrees with the 4 test reference cases described in ISO 10211:2017 (Thermal bridges in building construction) Annex C.

Tomek

Hi Victor, thank you for sharing these cases.
I have a question. I don't see any bonded contacts between bodies in posted files. However results are continuous. When I try to calculate thermal analysis (using cad STEP files for geometry) I find that I have to set up bonded contacts for heat to flow between bodies and that is really limiting me to only very simple assemblies. Is there a rule or something else I am missing?

Victor

In these models, the parts have compatible meshes and share nodes so there's no need for bonded contacts. If you use STEP files and automesh them, that won't usually be possible (though with Gmsh you usually can). If the different parts are the same material, it's probably better to combine them in CAD first.

Tomek

Do you mean automeshing using gmsh or importing premeshed geommetry from .msh file?

When I import parts one-by-one as STEP models I can not use Coherence mesh to make nodes shared. When I do it with one assembled model the result is not dividet into parts. When I make msh with Gmsh GUI I the parts are separated as I can't use coherence mesh in the process.

Any clue how to achieve that?

Victor

If you use Gmsh on a STEP file, then usually the same-shape surfaces end up with the same mesh so you can merge them together.

You can download Gmsh from http://gmsh.info/ and then connect Mecway to it and use it through Meshing parameters -> Gmsh and Options

If the problem of bonded contact is incompatible constraints due to multiple contacts on the same node, you could use the CCX solver and Thermal contact conductance with a very high value instead.

Tomek

For my case that doesn't solve the problem. Thicknesses and holes in volumes are taken into account and surface meshes are different. Do you think it is possible for future relases to make a function for automaticly setting up bonded contacts between adjacent surfaces?

Victor

I can't promise but that is a feature that people have asked for before and I realize it would be valuable.

Kaspars

Hi Victor! How did you manage to get total heat flow?

Victor

For case 4 Solution -> Surface integral then select heat flux X and External_surface and click Evaluate.