I'm trying to do a simulation of a sealed electronics enclosure with some heat sources inside it. The chassis of the enclosure itself acts as the heatsink to ambient air. There's an internal fan within the enclosure blowing air over the hottest point to spread the heat evenly throughout the enclosure. I'm seeing some strange behaviour though. The heat seems to remain concentrated at the hotspot without being carried around by the air. (I've checked and the flow rate and fan settings are fine).
Furthermore, what settings should I be using for this analysis more generally? I've set it up as an external analysis. Will this correctly represent the internal volume of air and the ambient air, or do I need to specify a fluid subdomain? And will the computational domain automatically keep the surrounding air at ambient temperature or will it heat up?
Oh and one more question regarding heatsinks. I know I can use Flow Sim's built in Fan to simplify the model rather than modelling the blades, rotation etc of a real fan. Is there something similar I can do for heatsinks? There is a passive heatsink in my model but I don't know how to represent that heat conduction in a simpler way while avoiding modelling all the fins etc.