Fan Stacking...

seppaku · 08-31-2008, 05:20 AM

i have thought about this alot and i really want to try it, you take two fans any size but for this plan i will use 120s take two fans and stack them together. both pointing in the same direction, if you do so would it increase your cfm? you could connect the fans with zip ties if you wanted to be ghetto. or i have a plan for a nice combo with 2 140mm XCLIO greens, 2 Scythe Kaze Maru, and a tempest case. i would remove the 2 140mm blow holes, cut of the "screw holes" for one side of the Scythe. then insert the fan into the blow hole its self instead of screwing it onto the outside of the chassis. at that point stack the XCLIO on the top of it and put the long screws (that came with the tempest) into the fans. i just got threw building a rig for a customer with the tempest, and that thing is a dream!!!

any thoughts would be great, thanks

here is the scythe

here is the XCLIO

and here is the blowholes on the tempest

importskyline22 · 08-31-2008, 11:47 AM

I dont know the technical reason behind it. But it has been discussed before at it will not work, they will almost cancel each other out.

Maybe someone will chime in with the tech reason.

furball zen · 08-31-2008, 12:22 PM

Quote:

Originally Posted by importskyline22

I dont know the technical reason behind it. But it has been discussed before at it will not work, they will almost cancel each other out.

Maybe someone will chime in with the tech reason.

Cavitation. A short definition, applies to air as it falls under fluid dynamics.

http://www.wisegeek.com/what-is-cavitation.htm

Basically, the air from the first fan will have to 'slow down' when it hits the intake of the second fan. More than likely youll see a reduced air flow. It will work when you have a smaller fan leading into a larger fan, with an air space between them. In other words, feeding a 120mm fan with a 80mm fan, with about an inch between them. The 80mm fan air wont slow down the 120mm air flow because its not totally blocking the intake of the 120mm fan. You wont see any benefits, at least not large ones, but in this 'case' it helped with the air flow because they werent fighting against each other.

If you have a tube with fans at each end, the air inside will move a little faster than with only an intake or exhaust fan, because the pressure is more constant. Take a 2 fan PSU for example, i have a TT 430W in my Static-X case and it helps keep constant air flow for cooling. But again, they have space in between them.

seppaku · 08-31-2008, 02:27 PM

Quote:

Originally Posted by furball zen

Cavitation. A short definition, applies to air as it falls under fluid dynamics.

http://www.wisegeek.com/what-is-cavitation.htm

Basically, the air from the first fan will have to 'slow down' when it hits the intake of the second fan. More than likely youll see a reduced air flow. It will work when you have a smaller fan leading into a larger fan, with an air space between them. In other words, feeding a 120mm fan with a 80mm fan, with about an inch between them. The 80mm fan air wont slow down the 120mm air flow because its not totally blocking the intake of the 120mm fan. You wont see any benefits, at least not large ones, but in this 'case' it helped with the air flow because they werent fighting against each other.

If you have a tube with fans at each end, the air inside will move a little faster than with only an intake or exhaust fan, because the pressure is more constant. Take a 2 fan PSU for example, i have a TT 430W in my Static-X case and it helps keep constant air flow for cooling. But again, they have space in between them.

i thought about this, and that is why i picked those two fans, the green fans cfm is 80 and the black fans cfm is 100 so if i put the black fan on top " the 2nd fan the air comes threw" and it already has air moving at 80cfm it wont amp it up with the other fan pulling at 100 cfm?

btw thanks for the help :)

furball zen · 08-31-2008, 10:21 PM

Quote:

Originally Posted by seppaku

i thought about this, and that is why i picked those two fans, the green fans cfm is 80 and the black fans cfm is 100 so if i put the black fan on top " the 2nd fan the air comes threw" and it already has air moving at 80cfm it wont amp it up with the other fan pulling at 100 cfm?

btw thanks for the help :)

Depends on how far away the fans are really. The air would still have to 'slow' down when it enters the top fan. I think if there is enough space between them, the top fan would have enough of a 'vacuum' to accelerate the bottom fans air to its air speed.

Why are you wanting to do this?

seppaku · 09-01-2008, 05:53 AM

more curiosity then any thing else, wondering if it would work. i am trying to play around with cheap cooling ideas, you never know when you could think of something revolutionary

furball zen · 09-01-2008, 05:30 PM

Quote:

Originally Posted by seppaku

more curiosity then any thing else, wondering if it would work. i am trying to play around with cheap cooling ideas, you never know when you could think of something revolutionary

True, but in this case, no. I would suggest just getting high flow fans instead of trying to stack them. Yate Loon makes a 120mm fan that flows 88cfm, Delta makes one thats 151.85cfm. If thats not enough air, stick your case to the side of an F-15....

seppaku · 09-01-2008, 10:04 PM

Rofl, yeah i seen those deltas in a thread here but the dba on them was in the 80s wasn't it? i decided im going to go with some yate loons and logisys because i want green fans my options are limited. i shouldnt have any cooling problems because im going to try out that kingwin gladiator water cooling hybrid cpu fan

furball zen · 09-01-2008, 10:55 PM

Quote:

Originally Posted by seppaku

Rofl, yeah i seen those deltas in a thread here but the dba on them was in the 80s wasn't it? i decided im going to go with some yate loons and logisys because i want green fans my options are limited. i shouldnt have any cooling problems because im going to try out that kingwin gladiator water cooling hybrid cpu fan

Ive heard bad reviews about them. I just decided against getting one. I got the CoolerMaster Aviva Duo for $35 shipped from Directron.com. You can use it for dual VGA or VGA/CPU. They have one thats single, but i cant seem to find it for sale anywhere, and eBay wants too much. You can just do what im gonna do, buy another one and use it for the CPU by itself :)
Its a self contained unit, but for that price, im gonna mod it in the future and upgrade the radiator. Ill post a pic of the waterblock, i purposely took it with my cell phone to show how good its lapped/polished.