CHT: Adding radiative flux Qr in interface patch

[jaydeshpande]

Hi,

First of all, thanks for the adapter. It is a great tool!

I am looking at adding radiation in the CHT case you have provided. How could we add Qr in patch heat flux at interface?

Thanks! Jaydeep

[MakisH]

Hi @jaydeshpande,

thank you very much for your nice words and your interest in preCICE!

At the moment, the radiation part is not included in the calculation. However, you could modify the file CHT/HeatFlux.C to add it.

I encourage you to fork the repository and try it yourself. If you manage to add this feature, you could then issue a Pull Request. If you already know the theory and have some validation case in mind, I can help you on how to implement it in the adapter.

Makis

[jaydeshpande]

Thanks Makis,

I will try to learn the flux balance more. I have a question for you --

If you have a regular buoyantPimpleFoam simulation - that is, without the solid interface - then you can simply solve for radiation assuming the interface as wall. Now the wall in temperature boundary, could be fixedFlux, fixedTemp etc. Now for the coupled simulation, if you use the same idea, that wouldn't require any modifications in heatflux.c right? buoyantPimpleFoam would still solve radiation and the heat flux would automatically appear at the patch?

[MakisH]

An instrinsic heat flux boundary condition would simplify the implementation, yes. But then we also need to make sure that this boundary condition is supported by several solvers, in several OpenFOAM versions.

Which boundary conditions exactly do you have in mind? I cannot find the exact names when I run buoyantPimpleFoam -listScalarBCs -listVectorBCs.

[jaydeshpande]

I couldn't explain properly. Here is a bit more detail.

For 'T' boundary in a buoyantPimpleFoam, you will either have fixed temperature or fixed gradient. For radiation, based on your emissivity and participating media/surface conditions, the "interface" will either gain/lose energy. The total energy balance, comprising of convection and convection would appear into a net heat flux in/out of the system. So, for PreCICE to handle gradients, it doesn't need to know if some portion of the gradient comes partly because of radiative loss/gain. As long as PreCICE couples the gradient back to the solid accurately, which it does, it will work just as well. What do you think?

I am planning on running a test case later today. I will let you know what I find out.

[TEFEdotCC]

144 add support for radiation flux in interface patch