Time-dependent solution

I have a fairly simple heat transfer model, in 3D. When I model it with time dependence it seems to provide a reasonable-looking solution. However, if I model it as stationary it won't solve. Postprocessing plot shows the one surface I input at fixed temperature, and the rest of the volume shows no temperature solution (just transparent).
I don't need a time-dependent solution. I have a feeling it is something to do with the boundary conditions. Any ideas?

Thank you for trying the software. With such a general description it would be impossible to say what could be an issue. Could you attach the model file either to the forum post or using a cloud file transfer service if it is too big?

I cannot post the geometry, as it is proprietary. I can try to make a simplified version and see if it exhibits the same error.

test2.fea

Hi, here is a model that shows very different behavior if the solution is requested as time-dependent vs. Stationary. The former produces a reasonable-looking result, while the latter is non-sensical. The system is a coating on a substrate, with the coating being heated and the substrate clamped on the edge, thus held at a fixed temperature on a ring.
Thoughts? I get the feeling that the way I define the objects or even the order I add them to the model affects the result. But I am not able to tell if I am doing something wrong in my setup.

Thank you for attaching a model file. With the default settings, the stationary solver does not converge likely due to the nonlinear radiative term ~T^4, so the solution can not be expected to be correct.

One can try to tune the solver setting by decreasing the nonlinear relaxation parameter and increasing the number of iterations. Or slowly increasing the nonlinear term and using the previously computed solution as initial guess. Also please check if all you boundary coefficients are correct, as some have the coefficient 5E-8 and others 1.5E-8.

Hi, thank you for the input. As the radiative term is significant in this case, I will continue with the time-dependent solver. Boundary conditions are correct, as not all materials have the same emissivity.