SimScale CAE Forum

Simulating Fan flow in CHT



I am simulating a heatsink assembly which is cooled by an axial fan sitting on top of it. The whole assembly is enclosed inside a fluid region in the CHT simulation. I created the ‘Enclosure’ in Simscale under the geometry tab. I am interested in the temperature profile of the heatsink when a power (say 50 W) is generated by the electronic chip, it is designed to cool. The fan runs on 2000 rpm to cool the heatsink.
I chose CHT simulation to model this setup. Couldn’t find a tutorial which shows how to model a fan in CHT, so after creating a ‘rotating zone’ geometry, I gave it a ‘momentum sources’ boundary condition in the Advanced Concepts. Also after creating the enclosure, I wasn’t able to specify a wall heat flux boundary condition to the chip, so I had to specify a ‘Power sources’ volumetric boundary condition. Did I model my simulation right?
After looking at the simulation results, I couldnt seen temprature change in the heatsink. It was as if the heat wasn’t conducted from the power source to the heat sink at all. The entire heat sink was at ambient temperature,
What changes do you suggest?
here is a link to the project:



Maybe one of our experts in the @CFD-SQUAD can help? Guys, could you assist Swapna in this case please? :slight_smile:




Hey @rasalsw,

As a matter of fact, I don’t think it’s possible to create rotating zones in conjugate heat transfer. Therefore, I’d suggest using a momentum source within a cylinder geometry primitive. To save mesh cells, I guess you can delete that cylinder + blades from your geometry.

Someone else might have a work-around though!


OK. I will try that and give you a feedback. Thank you!