CFD Online Discussion Forums - [swak4Foam] Fixed Wall Heat Flux with groovyBC

Hello FOAMers,

I'm currently trying to run a multiRegion case. I need a temperature dependent heat flux boundary condition with radiation and convection term on the outside of the solid (not coupled with the fluid). So I tried to use groovyBC. But there you can only specify the temperature gradient.

q = gradT * thermal diffusity

Code:

geh_out

    {

        type                         groovyBC;

        gradientExpression           "gradT";

        fractionExpression           "0";

        variables                    "Tinf=313.15;k=160;heatFlux=-(radiation+convection);gradT=heatFlux/k;";

    }

But I don't know which thermal diffusity to use. I tried the thermal diffusity from the solid, but the result was incorrect. Which thermal diffusity can I use?
In comparison to CFX, is there the possibility to determine a heat flux?

With best regards