Heat Sink FEA

[batman697]

Hello,

I'm starting to work on thermal FEA. Previously, I've only completed structural analyses so this is very new to me. I have a heat sink that I've powered up and measured the temperature of (using a thermocouple). Then I modeled the sink in CAD and I'm trying to analyze it. My problem is that I'm unsure of the material type. I'm guessing it is aluminum but my analysis doesn't exhibit nearly the same temperature range as my measurements (2 degrees vs. 11 degrees). I'm applying convection condition to the surfaces that reside in the ambient air and I'm using a convection coeffic of 10.

Does anyone have insights? My assumptions are wrong or my material is wrong. Does anyone know of any good heat transfer FEA tutorials?

Thanks,
M

 

[GBor]

Would you post an image so we can see a little more about what you are trying to do? And also what software you are using? There are several potential pitfalls. Making sure you have consistent units is a pitfall that I have landed in when trying to do Heat Transfer analyses. Also, if you don't have the right material, or if you have an air conditioner on when you ran your tests (forced convection?), or you breathed too hard in your test, or...or...or...to match your test with your FEA takes some careful attention to detail. Without knowing your material, I would guess that there is an incorrect input.

 

[spongebob007]

Not sure where to even begin with this one.

The convection coefficient is a function of flow velocity. For still air I tyipcally use about 5W/mK as an estimate.

If the heat sink is in still air, radiation effects may be significant.

There could also be issues with how you measured the temperature. Hard to really tell where things went wrong.