Wrong setup in a thermal flux problem

I have half a disk of concrete put in a water bath to freeze. I want to know in much time all the points of the disk reaches the temperature of the bath. I assume I can simulate the heat flow by ascribing to all the boundaries the temperature of the bath and an initial temperature to the domain, equal to the initial temperature in the disk. I selected Heat Transfer - Transient, input thermal conductivity and specific heat, however, whatever the time step may be, it seems that there is no evolution of the temperature and since the first written time step the temperature is everywhere that of the bath. It is like it solves the steady-state equation. I reduced the thermal conductivity up to three orders, no change. There is something wrong in the setup. Any help, please?

Hi @CFidelibus, thanks for posting on the forum and welcome to the SimScale Community :handshake:

Yes, I guess this should be a way to go about it! Keep in mind that this would simulate a condition where an imaginary solid with that surface temperature would be touching your disk. Perhaps a heat flux definition would be more appropriate.

It’s a bit tough to give a precise answer without access to your particular simulation. Could you attach a link to it? Maybe reading this forum post is also helpful!

However, you need to keep a few things in mind:

  1. For this sort of analysis, the end time should be more important for observing changes than the time step
  2. You should apply a cutting plane to observe the internals of the disk, the temperature on the surface will be kept constant as the value you’ve originally inserted
  3. Instead of using the Heat Transfer analysis type, you could go for the Conjugate Heat Transfer v2 option. CHT allows for interactions between solids and fluids but you can also only insert solids into it - and the solver is much more robust and full of features.

Cheers
Igor