How to mesh Conjugate Heat Transfer when there is no 3D model for the air

I took some hours to make more tests on the problem of failed run:

I started with a simple geometry and added more and more solids. For each geometry I did the same mesh and same simulation settings.

Test_model1+2+5 worked and finished the simulation.

Test_model3+4 failed to run.

From this I can conclude that the problem is with “fan body” but I have no idea why.

I’m running out of battery, will keep testing tomorrow

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Did more tests:
The system probably have some problem with the part “fan body”.

In simulation “CHT_test my model 4, none laminar” I tested all the none laminar solvers on a model4 (case + fan body). all failed.

In simulation “CHT_test mo model 6, new fan body” I replaced “fan body” with a new part with the same concept of inlet from top and exit to the right. this one did run.

so:
a) the error log just don’t help to understand to source of the problem (as it say totally nothing)
b) I have no idea whats wrong with “fan body”.
c) If I wish to continue with model 6, I have the value of the air flow from the fan outlet. putting that value in the outlet of the case is totally wrong. I need to be able to define the air flow from the outlet surface of “fan body2” (the circular face). Can I define this in SimScale?

thanks,
Momo