heat generation rate in the wall boundary conditions, what this?
 

Hi all,
If anybody may clarify, please: in thermal wall boundary conditions, the “heat generation rate” option relates to the heat generation where? In fluid or in solid domain? Is that heat generation in the fluid volume by the hot solid wall?
Thank you

It's the volumetric heat generation rate in the (solid) wall. It only works if you specify a wall thickness. It is part of the thin wall model, which is also used for modelling thermal resistances.

If you do use it, note that the normal wall boundary conditions are applied to the backside. That is, you can specify the backside wall heat flux or backside wall temperature with volumetric heat generation across a thin layer so that the temperature at the solid-fluid boundary may be less than the temperature that you specify as the wall boundary condition.

thank you,
but is there any way to generate the heat in the fluid domain, from some external source?
I don't care about the nature that source, what it do - generates the heat with known rate (w/m3)

and when you are talking about "backside", do you mean the outer wall surface, which is in contact with fluid?