[frossi]

Hi all,

I need to simulate the air flow in a laptop electronic compartment. The simulation needs to analyze the air flow in the compartment and the heat transfer generated by the electrical components.

The laptop compartment has an opening. Inside the compartment there is a fan that produces an air flow to cool the electric components.

I know CFX but I am completely new to this kind of analysis, for I never worked with electric components before. I know I am very general in my description, but I hope that someone can answer my questions and suggest how to proceed (so far I have been watching videos and reading).

1) Is it possible to simulate the fan INSIDE the laptop compartment that generates the airflow? If yes, how can I do it?

2) How can I simulate the hot electrical components and the effect of the heat transfer on the compartment and on the flow?

3) Are there other factors that I didn't mention that I may be important to consider?


Again, please excuse me for being so general, but I am looking for any possible advice on how to proceed.

Thank you very much to all.

[ghorrocks]

Firstly, ANSYS has a software package specifically designed for electronics cooling. It is based on Fluent. Maybe you should have a look at it.

If you want to proceed anyway using CFX:
1) Yes. You can either directly model it as a rotating machine or model its effect (ie the air flow it generates) with a momentum source term. While modelling the fan is the most complete and potentially most accurate it will dramatically increase the difficulty of the simulation. And as the momentum source approach is good enough in most cases, why make things hard for yourself?

2) Put the heat load of the components on their outside faces as a thermal boundary condition.

3) I can think of many issues but I have not read your mind to determine if you have considered them or not Some issues are:
a) I see a heat pipe device. How are you going to model that?
b) Generating meshes for these applications are tricky. What is your approach here?
c) You always need to do validations and verification on a new type of simulation. What are you going to do here?

[1994bm]

I wouldn't advise CFX for your work. Although quite easy to use for turbo machinery work, you need something called Icepak. Or at least use FLUENT. Icepak is FLUENT with tons of macros meant for electronics enclosures.