In Line Fans

[Haydan Tompkins]

I just wanted to ask if its OK to line up fans to make like a wind tunel, I'm worried that with the other fan pushing the one in front of it it might start stuffing the power supply up, I was thinking of doing something like this:
-------------------------------
F ----------> F ------------------> AGP
A ----------> A -----------------> PCI
N ----------> N -----------------> PCI
-------------------------------

so that the air flow got concentrated and directed over the cards instead of just pushed by fans at the front of the case toward the back. It seems to me that the amount of air movement must be quite a bit less by the time the air gets to the cards, espeacaly after it finds its way though the IDE cables

[SilverPriest]

Depends on what fans you use, but the gist of it as i understand it, as you will get sweet f/a CFM increase, but a higher pressure....
Was reading something about it either on procooling or oc.com about it.
You won't damage anything though.
And depends if the tube/duct/whatever is sealed TIGHT.
Can be beneficial, but i'm having a bit of a ahrd time picturing what you want to do, been a loooooong day :confused:
I say go for it and see what happens :)

[Haydan Tompkins]

I've never been to good at explainin stuff in posts

What I'm wanting to do is seal two fans up in a short peace of drain pipe, surround the fans with poystyrene to prevent flow back and seal the pipes end to the air intake grates at the forn of the case and aim the air flow at the cards.

Whats the deal with pressure and cooling? If I sealed the case up so that air could only flow out through the PSU wouldn't the increased air pressure in the case cause the air to 'carry' more heat?

That way I'd get a flow of air going over my cards displacing air up over the rest of the mobo, where it'd get out through the PSU. I have a 'kind of' tunnel between the CD roms that directs a flow of air over the processor and out the PSU that works well at lowering the CPU temp

But so long as having two fans, one in front of the other, dosn't pose a problem I can play around with it and give it a go

[_N_]

as long as they are not close toghter, and if one is slower and is sped up by the other, you will only generate electricity, eg, wind generator.. ;)

why not just use one fan, cause wouldn't it have the same effect if everything is fully sealed up?

[Haydan Tompkins]

Oh yea, true hadn't thought of that, what about the effect of air pressure inside the case and temps? If I restrict air leaving the case so that the air in the case is pressurised will that increase the effectivness of the cooling?

I'm thinking it would cause there'd be more air in contact with the heat sinks to transfer the heat to, and since hot air rise's if I had most of the air entering the case at the bottom and only exiting through the PSU at the top wouldn't that make the flow of air more effeciant at getting the heat out?

[I.R]

I've done that set up but with my CPU and then having a supply fan infront of that...... it's taken the temps down but I think the results would be the same using a tube :rolleyes:


http://forums.overclockers.co.nz/attachment.php?s=&postid=18286

[_N_]

well, you don't wan't air stuck inside the case, you wanna get rid of it ASAP, and you also wan't fres air in,
so basically, in an ideal situation, you would have say maybe a ratio of 2:3 intake : outtake fans respectively.

you can try to do this:
have heaps of fans blowing in, and under such high pressure the air leaks out by itself, i did this with 3 x 120mm fans blowing hard out into my midi atx before and worked great, the mobo temp was the temp of my room,

I had two on the side, one above the PCI and AGP
and the other above the CPU and Chipset

and 3rd on on the top blowing fan in, this would have been better if it was extracting the warm air,
but under such high pressure it made no difference,

[KingJackal]

I am beginning to see a disturbing number of figures without any scientific proof as to their accuracy or precision....

....yep, it's another air-pressure/water-pressure/heat-movement-patterns thread :rolleyes: :p

I would imagine that putting a fan either end of a tube would be less effective than aiming two tubes at the area to be cooled ( each with one fan ). Evidence? Not a whole hell of a lot - except ( thing laterally ) to notice that you don't see too many propeller aircraft with two sets of propellers with co-axial propeller axel's now, do you? ( or prop boats for that matter ) Most use one prop per axel, and maybe add a second prop - to a second non-coaxial axel.

.....

well, just my $0.02 as usual...

[dustyslapper]

Hmmm yeah - you want increased air velocity at the tube exhaust right?

Then put only one fan at the end of the tube - it will draw all the air it needs from the vent(ed tube). Putting a fan on the outside also would seem to be a bit of a waste of time, unless of course the tube is long and the air is struggling to get through.

As its a short PC case tube I would put one on the exhaust where you want the velocity, and that would do. Unless your tube is enormous - like over 40cm say - then you might want two fans. Makesure the tube is sealed, and it's easy for air to pass through (ie tube is straight and smooth) then you should draw through all the air your fan needs at the exhaust.

As you currently have no ducting but you really want fresh air, put a damn duct in.:D