[Zolmi]

Hello,

First, it's my first message here and even if I've read the "Guide: How to ask a question on the forums", I may be misusing this space, so feel free to tell me. Besides, English is not my mother tongue so I apologize for the grammar/vocabulary mistakes/inaccuracies.

I'm currently evaluating different solutions to simulate convection and conduction in electrical cabinets and I'm looking for feedbacks concerning ANSYS AIM. I've found few specific questions regarding this tools but I haven't found a global opinion on this tool.

On the paper this tool looks great and well suited to our need : it's user friendly and built to be used by people like me, not expert in the finite element calculation. Besides fluid, it has got lots of others possibilities like mechanical or electromagnetic possibilities but I wont get further on those because it's not the topic of this forum.

My need is :
I have an electrical cabinet with many heat sources (electrical components) that I want to cool down using different means :
- Cold plate directly on the component
- Water/air heat exchanger to cool down the air inside the cabinet
So it includes convection in two fluids (air and water) and conduction (in cold plates). Also, there will be some fans inside the cabinet and I would like to use their P-Q curves.

I want to design the cooling system of this electrical cabinet by using simulation

I've been using the tool (ansys aim) for two weeks now but I struggle to be sure if it's suited for my need. I have problems to converge on very simple cases and when I converge, I have really strange results. That's why I'm doubting about the ability of the tool to solve my problem.

I know solidworks flow can achieve this (with certain assumptions like considering the water/air exhanger as a porous medium with heat sink power as a function of the entrance temperature and fluid flow) because a subcontractor was doing it for me few years ago. Now I want to implement this skill internally that's why I am wondering about the good software to do it.

You could tell me, if SWF is doing the job, why not using it ? Because its much more expensive than ansys aim and I can't be blind on it.

So my question are :
- Is any of you using Ansys AIM in a professional environment ?
- What kind of limitations Ansys AIM have you noticed compared to CFX/Fluent/SWF ?
- Which software would you advised me regarding my subject ?

Thanks a lot for you help

[tpd]

Hi!

I am working with exactly similar problems. I have limited experience on AIM but I could make some notes for you. It is meant to be a simple multiphysics code for non-experts. It is hard to say how it fits to your case exactly because it very much depends on the level of geometrical and physical detail you want to resolve in your cabinet. Meshing is in practice tetrahedral only (limited extruded mesh capability). It is fine unless you have for example large high aspect ratio heat sinks or other thin geometries. Tetrahedral mesh becomes very large in those kind of geometries.
You can have as many fluids and solids as needed as well as natural convection. It is not a problem for CFD codes in general.
AIM does not have thermal radiation heat transfer capability but if your problem is dominated by forced convection you do not need it.
AIM neither has a built in fan type boundary condition so you have to use some simple scripting language to create a fan.

If you want to model a complete cabinet with liquid cooled cold plates and similar level of detail you are going to have a very, very large mesh despite of the code you are using. Laptop is not suitable for solving this large problems.

I am mostly using Fluent. Fluent has much more capabilities in solving different kind of fluid flow related physics but most of them are useless in yur case. Meshing is very advanced in Fluent. Actually Fluent can work with any kind of mesh. But it is more complex software with steeper learning curve. And much more expensive.

Ansys Icepak, Flowtherm or other similar software might work for you because they have built in customizable models for many electrical components, fans and other cabinet components.

[tpd]

Want to add one more comment: If you have troubles with "simple" problem convergence and strange results I am quite sure you are not setting up the problem correctly. Very rarely it a software related problem (allthough I have seen it, too).