[zfaraday]

Hello FOAMers!

I am studying a simple case with chtMultiRegionSimpleFoam (just to practice the set up for radiation and heat generation) consisting of 2 cubic solid regions (one is generating heat power, actually its temperature is defined as a constant of 600K because I still don't know how to set up a volumetric heat source) surrounded by a bigger cubic region of air. All of the boundary faces for the air region are isolated (using externalWallHeatFluxTemperature wit q=0) except one (defined as externalWallHeatFluxTemperature with Ta=293K and h=1).

The purpose of this simple case is, of course, study what happens when the heating region heats the whole system, either considering radiation or not.

Then, here comes the point! I executed the wallHeatFlux utility to check the energy balance in the system and I found something that is making me crazy. Below you can see the results I got.

air
Wall heat fluxes [W]
maxY -63.0738
minX -0.003706714
maxX -0.009187714
minY -0.0116676
bottom -0.002245114
top -0.002884371
air_to_heater 141.7464
air_to_object -73.04159

heater
Wall heat fluxes [W]
bottom 0
heater_to_air -141.74

object
Wall heat fluxes [W]
object_to_air 24.3712

As you can see the heat absorbed by the object (yes, I know, it's the most original name for a region anyone has ever heard) is not the same that goes from the air to the object. Furthermore, right now I realised that the energy in the air is also unbalanced since there is a difference of 5W between then energy coming in and going out of the air domain.

Have anyone experinced something similar any time? Am I doing anything wrong? Is there something going wrong with the utility? Any hint or advice will be more than welcome!


Thanks in advance!


Alex

PS: The results are extracted fom a case without radiation, but the same occurs adding the radiation component.