Gorka,
I don't think I understand your problem. Is this a container filled with water, and you want to analyze the heat conduction in the water, assuming it does not flow around? This is perhaps the case if your container is very small; so that the flow resistance against the walls keeps the water in place. But if the container is of some larger size, then the water will start circulating if there is a temperature gradient.and I would assume heat transfer through convection will dominate over conduction. In that case the temperature field will be considerably different compared to what you would get assuming the water does not move.
FloEFD is a CAD-embedded simulation software that can model the coupled heat transfer / flow problem, but Creo Simulate can't model flow, only heat conduction in solids.
As for the heat flux lines that you are looking for, it should be possible to extract the results (temperature, heat flux etc) from the Creo Simulate results files, then import points on ISO-curves to Creo as datum points and then create the datum curves. I have done this for stress results. I wrote a script in Matlab that extracts data from the Creo results file.
Best regards Mats L
