Good place to learn about air flow

[Sancho9000]

Hey everyone,

Just started dipping my toes into hardware modding. Planning to do a bunch of research first before I jump all the way in.

My question is, is there a good resource to learn about air flow requirements? e.g. is there an optimal layout for optimal air flow? or are there certain rules when designing a case that I need to be aware of?

I imagine cramming the circuitry into a tiny custom case is bad, so what would be good to keep in mind?

Thanks!

 

[Prog]

Few of us really put tight engineering constraints on our projects.

It's rare to see much technique beyond "don't remove too much heatsink, anything newer than N64 add a fan, and it should suck away from the heatsink. Also keep the hot stuff away from batteries."

 

[laingsoft]

There is a lot of complicated math to go with it, but essentially it boils down to this:

The smaller the effective surface area of your heat sink, the higher flow rate of air you will need.

If you want to get really into it, you'll need to start looking at heat transfer and all of the fun physics of a fluid flow. Basically you want to get turbulent airflow through the channels that are generating heat rather than laminar (smooth) flow. This is because turbulent flow exposes more of the cooler air to the heatsink. Turbulent flow will happen when the Reynolds number is really high. Because you aren't going to be able to change the pressure or density of the air in your system, the only two things that can affect reynolds number is flow rate and diameter.

So if you really want to, you could start looking at that, but in all honesty, doing the math isn't worth it, both because it's a hobby project, and also because your portable isn't generating that much heat. Just having open channels and a fan is more than enough.

Here are some links:
https://www.princeton.edu/~asmits/Bicycle_web/transition.html
https://en.wikipedia.org/wiki/Reynolds_number
http://www.advantageengineering.com/fyi/156/advantageFYI156.php