Article: Fan passive noise reduction

Control: management of fans, temp/rpm monitoring via soft/hardware

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Olle P
Posts: 637
Joined: Tue Nov 04, 2008 6:03 am
Location: Sweden

Re: Article: Fan passive noise reduction

Post by Olle P » Wed Oct 31, 2018 11:02 pm

Interesting article!

Pop Quiz:
Looking at the noise/frequency graph on the third page, ...
1. What was the fan speed?
2. How many blades on the fan?

Hint:
There can be a merit in playing submarine sims...

Olle P
Posts: 637
Joined: Tue Nov 04, 2008 6:03 am
Location: Sweden

Re: Article: Fan passive noise reduction

Post by Olle P » Wed Oct 31, 2018 11:58 pm

A reflection of mine is that the exhaust diffuser cone is pure rocket science.
Not as in "difficult" but as in "how to define the proper shape and size of the end bell".
On a rocket engine you want the exhaust gas pressure to be identical to that of the surrounding atmosphere at the point where it leaves the bell. The same apply to the fans here.

lodestar
Posts: 1683
Joined: Fri Aug 05, 2005 3:29 am
Location: UK

Re: Article: Fan passive noise reduction

Post by lodestar » Thu Nov 01, 2018 3:20 am

Overclock.net wrote:...One solution to reduce the noise generating disruptions to the inflow is to deploy an air straightening grill on the fan intake.
There was of course the Nexus BeamAir which was designed to do precisely this but never caught on.

Image

mcb
Posts: 32
Joined: Sat Aug 24, 2002 10:24 pm
Location: San Francisco

Re: Article: Fan passive noise reduction

Post by mcb » Thu Nov 01, 2018 10:44 am

This article (nice find!) suggests a flow straightening grill on the intake side - the Nexus BeamAir seems to do this on the exhaust side.

jango1985
Posts: 2
Joined: Tue Mar 28, 2017 1:50 am

Re: Article: Fan passive noise reduction

Post by jango1985 » Thu Jan 03, 2019 6:07 pm

This got me googling and I came across an article about the noise impact of different grill patterns. https://www.pugetsystems.com/labs/artic ... Noise-107/

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