Cooling fan mod.

if you fitted a 12v computer type cooling fan to the heat sink of an amp or any device to help cool it ... Which way would you sit it?  ie. would 'blow' down air onto the heat sink - or mount it the other way to 'suck' hot air off the heat sink ?

I want to mount this little fan directly over a heat sink... but not sure which way of mounting it will get the best (coolest) result.

Cheers all.

Matt

Hi Matt,

You could go all "fluid dynamics" and argue this one to infinity

From my many years in the electronics sector it was usual to suck air out of enclosures and blow onto heatsinks. This history often gets forgotten and randomly picked nowadays (!)

I'd personally blow onto the heatsink, this prevents dust accumulating on the heatsink and then you aren't sucking heat through a delicate fan
Don't forget positive pressure either, mount the fan too close to a heatsink and the pressure can build up slowing down or stalling the fan so often small standoffs were used to prevent such problems.

That's my personal opinion anyway

Hope that helps,
Victor

Victor wrote:

Hi Matt,

You could go all "fluid dynamics" and argue this one to infinity

From my many years in the electronics sector it was usual to suck air out of enclosures and blow onto heatsinks. This history often gets forgotten and randomly picked nowadays (!)

I'd personally blow onto the heatsink, this prevents dust accumulating on the heatsink and then you aren't sucking heat through a delicate fan
Don't forget positive pressure either, mount the fan too close to a heatsink and the pressure can build up slowing down or stalling the fan so often small standoffs were used to prevent such problems.

That's my personal opinion anyway

Hope that helps,
Victor

Brilliant Victor - Once again Thank You very much indeed.

I'll pop small spacers of some sort in the mounting to allow that positive pressure to flow away and taking the heat with it.  

Cheers!

Matt.

OK, yeah I'm responding late to this but for reference.......... :

As Victor says,

The fan would be best blowing onto the heatsink (in the same way that a processor fan blows onto the processor heatsink in a PC).

If the entire device is inside an enclosure / box / etc, then another separate fan should suck air OUT of the enclosure (in the same way a rear case-mounted fan does on a PC case - the air is sucked out of the PC and blows into the room).

With regards to mounting, I have read that some people push small squares of cork in between the heatsink fins and then screw the fan down onto these.
Saves drilling the metal or making a mess with glue.

Hi Rory,

It's never to "late" to add anything
If a posting is useful or anything useful can be added it should recirculate whilst people find it such.
(I like to go back over postings myself, always find something useful.)

I've seen the cork method you mention and if it works for you, all is good. Makes sense, easy to fit, easy to screw into, provides vibration dampening, etc. I'm personally an engineering P.I.T.A. so out comes the small drill bits and taps.....mmmmm, nothing like a cleanly drilled and tapped hole.....OK, I'm a weirdo I know

All the best,
Victor

There are no weirdos in this hobby Victor! We love to get meticulous with tech - that's why we do it. right?