Hello,
I am currently working in a thermal - structural model for a furnace steel structure. Specifically, in the thermal analysis, I set up a boundary condition of temperature in the interior metal wall (50 C) as well as in the sit of the burners (70 C). In addition I have a convection condition in all the exterior walls (10 W/m^2 K for an ambient temperature of 30 C).



Due to the maximum temperature that I have established (70 C max.), as well as the fact that doesn't exist any other kind of heat source, I expected to get a thermal distribution with a maximum value of 70 C in the area that I have specified. But in reality I'm obtaining a distribution where the maximum temperature is 72.1 C.

Why is the model reaching a temperature over the boundary condition?
PD: The whole structure is made up with steel. I have already checked the thermal properties of the material and there is no problems there.
Thanks,
Regards.