[Saketh Bharadwaj]

Hello,
I am trying to model a 3D heat transfer problem in COMSOL v6. The geometry is very simple and attached below. The length of model is 2m. Rectangular block is 200mm * 160mm.
The point of interest is to calculate equivalent thermal conductivity of air. Thermal conductivity of air in this region depends on all 3 types of heat transfer. Radiation is from the enclosing material (Insulation material on inner side and steel on the outer side)
Conduction and Radiation can be modelled easily. But including the convective effects is little tricky. Ideally, whole of the system should be simulated with induced velocity. But including a lot of physics is making the computation tediously long.
Does anyone how to model this case? One way is to consider analytical Nusselt number correlations. But I do not know how to couple this correlation as my model is also dependant on radiation.

Thanks.

Saketh Bharadwaj