That's an unusual application for a fan.
You do not want to plug these into a wall outlet. Outlet is AC. Fans are DC.
OK. If you are sure that a 12 volt computer fan (or fans) will move enough air to be useful, here's how I would do it ...
Get a cheap computer PSU. It doesn't need to be a good one. You are not going to load it that heavily. Most 12 cm fans pull around .2 amps. So you can power a lot of fans from even a cheap power supply.
Select your fans. If you are not going to be around much when they are running, select for airflow instead of noise (the two are pretty much inversely proportional).
Plug them into the IDE drive molex connectors. You may need "Y" adapters if you have more fans than connectors.
Now you need a way to turn it on. Simplest low tech way is to use a paperclip to short the green wire on the main PSU connector to one of the black wires (ground) on either side of it. This is a low voltage control lead - no danger of shock.
Only other problem I see is environmental protection. That's up to you.
If you decide to do this, let me know how it goes.