CFD Online Discussion Forums - How to impose radiative boundary conditions

Hi all,

I am facing a problem imposing radiative boundary condition for a heat tansport problem using OpenFOAM 11.

To be more precise the condition i would like to impose is on surface flux q:
$q = \epsilon \sigma_{SB} (T^4 - T_{env}^4)$
Where T is the temperature evaluated on the surface.

The closest type of BC I found is "externalTemperature" that seems suitable for convective boundary conditions. It also allow to set an emissivity but it is not clear to me how it works since I am obliged to define also a heat transfer coefficient.

A way to solve the problem could be writing a temperature dependent heat transfer coefficient in order to account for radiation, something like:
$h = \epsilon\sigma_{SB} (T^2 + T_{env}^2)(T + T_{env})$
It should be easy but I couldn't figure out how to do that.

So, how can I impose radiative BC?