Guys/Gals,

I have spent a few hours searching the forum and could not find an answer, but my apologies if it is out there and I couldn't find it...

I am looking for help on the best method for modeling radiation heat transfer from a heat sink.  Specifically, I am modeling a PCB with various ICs/heat sinks enclosed within a vented plastic enclosure.  There is no fan so convection is natural, driven by gravity and the temperature gradient.  I have read that radiation can account for up to 25% of heat transfer under natural convection, so I don't think I can ignore this despite the relatively low temperature of the heat sink (100degC).  Additionally, one of the key specifications is the outside enclosure surface temperature, this cannot get too hot or it will be dangerous for consumers to touch.

Basically, I am confused about the proper application of "environment radiation", "radiative surfaces", and "radiation sources".  I have read the help files and tutorials, but I am still confused.  I would like to know both "how to set up this analysis" and "why you chose that set up method".

Thanks,

Jason