Question squirrel cage vs rotary

[GunsMadeAmericaFree]

I was wondering why computer cases don't use squirrel cage/centrifugal blowers to move air. I was replacing the furnace filter in
our house the other day, and noticed that it uses one. I also noticed that cars use them.

Why not computers?

 

[BoomerD]

Noise, amount of space required, costs.

 

[Tech Junky]

It would require a huge case or externally mounted. i.e. people wouldn't want to look at it.

 

[GunsMadeAmericaFree]

Noise, amount of space required, costs.

? Are they inherently louder when moving the same amount of air?

 

[yottabit]

? Are they inherently louder when moving the same amount of air?

Basically. Radial fans are better for higher static pressure. The two applications you described (furnace/ac and automotive hvac) both involve forcing flow through long series of split ducts that necessitate higher pressure

A PC case by comparison is less restrictive and needs lower air velocities.


There’s also the packaging issue of radial fans draw air in orthogonally to their output direction. So generally for such a blower you have a big volute or shell enclosure that helps direct the flow from / to where it’s supposed to go.

Squirrel cage type fans were used in PCs for the older rear exhaust “blower” GPUs which are again closer to a ducted flow. For same CFM an appropriately sized axial fan will almost always be quieter.


Radial fans are also used in laptops where the packaging is convenient for a bottom intake, rear exhaust design and axial flow through would be impractical.

 

[aigomorla]

You know sometimes i asked this question myself.
Like on racks, where you need to move air in a pizza box, a centrifugal fan would be WAYYYYYY quieter then having 6 x 40mm screamers pushing air though the case.

But i think it has to do with vibration control, and longivity.
Tower Fans by nature are higher prone to failure then a standard box fan.
And i think laying a tower fan sideways with the torque on the motor would lead it faster to failure.

But they do have those fans for laptop coolers, and they work really well.
They call them cross fans tho..

Cross fan