Temperatures in Creo Simulate Live Fluids always diverge to infinity

[ggoss]

In Creo Simulate Live Fluids, every system I try to model that includes a heat load (or object with a prescribed temperature) results in the whole system rapidly diverging to infinite temperature. As an example, I would like to model free convective and radiative heat transfer from a simple system consisting of a small hot body attached to an aluminum heatsink (above) and a thin copper sheet below, floating in air, but have been unable to model this in such a way that the temperature of everything does not rapidly diverge to infinity. Analogous simulations in Live Thermal behave as expected.

Is there something I'm missing? Anyone have an example of a model of a simple PCB with chips and heatsinks in air (or similar) with a live fluid sim setup that works?

I have been unable to locate any examples or validation models for Creo Simulate Live Fluids in the Creo documentation (the documentation for this extension is really sparse), but would love to review such items if they exist.

I am using Creo Parametric Release 8.0 and Datecode 8.0.2.0, and get no error messages.

[sacquarone]

Hello @ggoss 

As a first approach, you may like to get a better understanding on how to configure this kind of studies in the Tutotial we propose in our Creo Parametric Help Center.

Based on my understanding of your business need, I think you'll be interested especially on following ones:

• Tutorial 2 (Beginners): Power Inverter with Conjugate Heat Transfer
• But especially this one: Tutorial 2 (Advanced): Cabin Radiation with Convection and Radiation

Hope this will help, at least for a first assessment.

Regards,

Serge

[ggoss]

Thanks @sacquarone. Unfortunately, I only have access to the Live Simulation Fluids Package (and not the Flow Analysis Package), and these tutorials do not port over to the Live Simulations Fluid Interface at all. Are analogous tutorials for the Live Fluids Package available?

[sacquarone]

Hello @ggoss 

oh ok, sorry for initial misundrestanding. Indeed, actually what you need seems to be more appropriate to the scope of Flow Analysis, rather than Live Simulation Fluids.

That being said, regarding Live Simulation Fluids, yes, you have also access to examples (with downloadable model) in Example—External Fluid Simulation in Creo Simulation Live section of Creo Parametric Help Center. Just consider however that this study is oriented to use input like Flow Velocity, Outlet Pressure & Slip Symmetry, and not really convective and radiative heat transfer as it was possible to do in the scope of Flow Analysis.

You may prefer therefore guidance in Example: Thermal Simulation section, where you define as input:

• Heat Flow Loads in mW, and Boundary Conditions
• with convetion coefficients in mW/mm^2 and prescribed temperatures in degree C.

Regards,

Serge

[ggoss]

Thanks Serge.

The external fluid flow example seems to work fine. Is there a model available for Example: Thermal Simulation? I can't seem to find one for that to run and compare the results against. This is a very similar (but more complex, with 5 heat loads instead of 1) setup to the test case I am having trouble with (where the temperatures either diverge or settle around a very high number, like 5000 C).

[sacquarone]

Hello @ggoss 

The Help Section discussed earlier is dedicated to give guidance for this kind of studies, but do not propose any model to download. The only section of Help Center where you have most of our models ready to be downloaded are the ones included in Tutorial section of the Help Center, but as you can see, if we propose things for Creo FLow Analysis module, we do not propose any for Theraml strudies in Creo Simulate Live environment.

For CSL & Thermal, you have on Case study downloadable if you want starting from Verification Guide—Creo Simulation Live and Creo Ansys Simulation, but I'm afraid that this Thermal SImulation is very far from what you are looking for.

I hope this will help a bit anyway, as I'm afraid that I won't have much more documpentation to share in the direction of tutorials in CSL Thermal.

Regards,

Serge