Thermal Modeling w/ Ansys or Flotherm

[FrancisMarquis]

In my group, there's the guys that build thermal models using Ansys and other using Flotherm (our only two thermal modelign tools). In both case, the configuration is similar: chip on carrier on PCB on cooling plate, conduction only. The detail level is quite detailed (die-level conductors and thermal vias, dia attach voids). Both Ansys and Flotherm great correlation to test data. So it comes down to a preference is which tool is used until we add forced convection or radiation.

I would like to get other members' opinions on the tools. Looks to me like Flotherm is much easier to work with except when it comes to importing CAD geometry (from ProEng for example).

I welcome members to state the tools they like to use for different thermal analysis scenarios.

Regards,

Francis Marquis
Mechanical Engineer
Telecom/Electronics Industry

 

[tkordyban]

ANSYS is superior in conduction-only problems, because it can easily import any arbitrary solid geometry from CAD. FLOTHERM can solve solid conduction problems, but approximates all geometry as combinations of cuboid blocks and flat plates.

You already answered your question when you said FLOTHERM must be used to consider air flow and/or radiation. ANSYS handles air flow heat transfer only by you specifying the heat transfer coefficient on each surface, which, of course, you don't know. So if you have fluid flow carrying away heat, FLOTHERM is the only proper way to solve it (or another CFD program like FLUENT.)

These two packages are intended to solve different problems (ANSYS is mainly designed to solve structural problems). It is only in the area of solid heat conduction that their capabilities overlap.

 

[ko99]

Francis,

For the same reasons mentioned by you and Tony, I use CFD (Flotherm) for thermal analysis.

However, your's sounds like a rare (for me) conduction-dominated problem and FEA should work fine, particularly with the amount of geometry detail you want to import.

FYI, if convection or radiation is, or becomes, important, or if you want to use the IC in a larger model, I suggest you use Flotherm's Flopack tool to create the IC model rather than importing the CAD geometry.


ko (

http://www.ecooling.biz)

 

[pulsetech]

Have you checked out the Cosmos Works product?

http://www.cosmosm.com/pages/products/analysis_thermal_works.html

It interfaces direct to SolidWorks so the CAD deisgn import is just a click away. I believe they have a version for Pro E as well....

Our engineers find this easy to use and cad conversions are not an issue. Hope this helps.

Ken

Pulse Designtech