Learning Forum

[dirk.linnenbruegger]

Dear Forum,

I’ve set up an internal flow simulation that works quite fine, although I’m using a complex design, existing of an housing with integrated PCB and some STEP-file components on it. i.e. heatsink.

However, since I also would like to analyze the thermal conditions, I’ve added a tempearature of 150°C to the heatsink.

Now the temperature simulation shows no results.

So, I’ve updated the simulation bodies and run the temepature simulation again.

Same effect aspreviously, No simulation results, althogh I’ve reduced the fidelity to minimum, resp. speed to maximum. Even if I go for a coffee break, the computer is running with maximum CPU/GPU spped but no results.

Basically this kind of simulation setup should run, as my prototypes show, where I’ve included a small PCB with IC and heatsink into a housing.

 

So, does anyone has an idea what’s going wrong here? Does this effect goes ahead with the complex simulation environment?

 

Just an additional remark:  once I set the heatsink as simulation body, the program crashes immediately.

 

Thanks for your reply

Dirk

[Subashni Ravichandran]

Hello dirk. linnenbruegger

Is it possible for you to share the file with us for investigation?

I have shared the ANSYS Secure transfer link with you via email. 

[dirk.linnenbruegger]

Dear Subashni,

many thanks for your reply.

The demo board contains confidential data, so it’s not allowed to be published within the forum.

But of course it can be used for your investigations.

Regards

Dirk

[Subashni Ravichandran]

Hello dirk. linnenbruegger

Thank you for sharing the model.

We could replicate the issues you have listed.

The heatsink component 'ICK_S_29x29x20' is not being simulated and if it is 'Set as Simulation bodies', Discovery Live stopped working.

I have filed a bug ( Bug 154717 ) and forwarded your file to the Development Team.

The workaround I would suggest is to manually cut the Heatsink component from the Flow Volume using the 'Combine' tool.

Make sure to define the Temperature boundary condition to the surfaces on the 'Volume' component and not on the Heatsink component.

[dirk.linnenbruegger]

Hello Subashni,

I'll try to follow your suggestion and I'll let you know once some questions should arrise.

Thank you

Dirk

[dirk.linnenbruegger]

Dear Subashni,

I’ve simplified my setup to the IC with heatsink only positioned inside a housing.

However, this smaller setup shows the same effect as mentioned above.

In addition, I’ve modified the heatsink body into faces as you mentioned but I also cannot get better results.

So, I’m a little bit struggling of how to resolve this problem.

The most challenging problem is, that we started to promote DiscoveryLive and I have to demonstrate the tool within a public webinar at the beginning of September.

So, finally we need to find a practicable solution quickly. I hope that you can help me.

Once it is helpful for you, I can upload the modified files to you as well.

 

Thanks and best regards

Dirk

[Subashni Ravichandran]

Hello dirk. linnenbruegger

I understand the difficulty you are going through. 

I opened the heatsink alone in a new file and I was able to simulate with it.

 

Cutting the heatsink manually from the 'Volume' component is the only workaround I can think of.

I have shared your model with the team. I will get back to you as soon as I hear from them.