Performance Vs Noise - Experimentation

[Stocky]

Marci']Also recommend a request for testing methodology from the guys at forums.procooling.com - if you can replicate their methodology then all your results will be directly comparable to theirs and can then be used for performance modelling purposes for radiator testing and suchlike.

Just pop a post up asking where to locate sensors to best measure a fans performance - distance away and in which quadrant etc.

Original Thread:http://www.extremeprometeia.com/forum/showthread.php?p=33234#post33234

Okay, got that out of the way - that juat about explains why this thread is here :)

I have the following test equipment - I know it's not near the best but it will provide myself and others with a way to compare different manufacturers fans.

DAWE Sound Level Meter (797900)
Tenma (726638) Anemometer

Fans (so far collected):

AeroCool Turbine 1000 Fan
Cooler Master A12025-12CB-4KN-L1 PL12S12L
A.C. Ryan 12CM UV fan
SilenX IXTREMA IXP-74-14
Akasa Model: DFB122512L
Akasa AK-183-L2B Orange
AcoustiFan 120 AF120C
NMB Model: 4710KL-04W-B10
PANAFLO Model: FBA12G12H
PANAFLO Model: FBA12G12M
Themaltake Thunderblade Model: TT-1225

That's it for now. But will continue to add more :)

The current proposed test methodology will be:

Fans measured in free air
The fan will be measured 1 Meter away, horizontal to the dB sensor.
I have an mCUBE digital which I believe uses PWM to power the fans, however not all the fans respond well to it - the Ryan goes nutty.
So using both methods to power the fans would be a good idea, especially with PWM becoming more and more popular.

More details can be found on the original thread at EP-UK.

Please advise, constructive criticism welcomed - I want this to be a useful resource for others :)

[Stocky]

C'mon folks this is spose to be a useful resource for everyone. Marci pointed me here as you guys are meant to be the more intelligent cooling poeple :D

Upgraded the CFM meter to:

CFM MAster - DCFM8901

[bigben2k]

Why don't you start by listing exactly what you want to test on these fans?

-Noise
-actual airflow

Does that sum it up?

For noise, ideally you'd have a soundproof room (or enclosure), and a sound recorder for which you know the characteristics, throughout the human sound spectrum.

For airflow, you need a fan testing chamber.

U need links?

[Etacovda]

sounds like a good experiment to me.

Get marci to send you a pa.120 too ;) and see if you can get hold of a heatercore, and one (or both) of the black ice series to test pressure resistance vs noise - that would be especially useful here.

[BillA]

Note that a thermal anemometer reads the air velocity over the sensor, how do you intend converting that (local) velocity to CFM through the fan ?

what is the mic floor (lowest level) ?

[bobo5195]

I woudl of thought a thermal anemometer woud convert all that stuff internaly either that or there is an ASME, ISO etc spec on it.

[bobo5195]

While I’m here, and sorry if this sounds like random facts. I type like a robot apparently.

You’re going to want to measure back pressure and its effect on noise there is also some effects of near fan geometry causing excess noise. This is noted very handily in the BTX spec, basically the dominant sound frequency you should get out is caused by the fan blades interacting with the supports. This is why artic silencers suspended fans are so good as the fan supports are so far away even though having no shrouds makes them awfully inefficient as fans. To create a back pressure maybe a long duct with an orifice plate (a plate with a circular hole) this should create a back pressure to work with. Measuring without a back pressure is pretty much pointless as all fans are subjected to one. There is an effect as well of air recirculation back around to the entrance from the exit. If the fan is completely free and some back pressure being caused by momentum conservation if it’s hanging from springs (the suspended springs move as the fan creates a force trying to balance the momentum of the air out, so it deflects to balance everything out).

One thing to remember about thermal anemometers is they like a nice uni-directional flow so it might be better to put some lamina flow guides in. This may be nothing more than a box grid made out of paper but it should help. I’ve never used the things 9themral anemometers) myself though, so you may get away with it.

On the sound pressure meter make sure to measure when there is less noise about. If your in a built up area this means staying up late or getting up early. And keep the measurement point and microphone direction as this will help make sure the measurement is a constant.

[BillA]

ah, 'free flow' ?
speed bumps ahead

[Etacovda]

One thing to remember about thermal anemometers is they like a nice uni-directional flow so it might be better to put some lamina flow guides in. This may be nothing more than a box grid made out of paper but it should help.


A friend of mine was doing some self-made airtunnel testing for some sporting equipment - he used a bunch (probably nearing or exceeding 1000) of straws glued together to make a honeycomb arrangement. Too much pressure drop for this situation, i think - but it was an interesting solution.

[bobo5195]

I was thinking more cross hatch from a ice cube tray (preferably for making small ice cubes). I swear ive seen a plastic grid around somewhere, in something common that would be useful. Could try acetate slides for overhead projectors.

[BillA]

A friend of mine was doing some self-made airtunnel testing for some sporting equipment - he used a bunch (probably nearing or exceeding 1000) of straws glued together to make a honeycomb arrangement. Too much pressure drop for this situation, i think - but it was an interesting solution.
thats the correct soln but does have a dP, lengths and dias speced (for turbine air mtrs ?) of x tubes inside a tube
none of this is possible as he wishes to test eh ?

[UNDERBYTE]

Testing free air tells you next to nothing, fans can change 10 dBA as you go up the res. curve.

Standard practice usually involves an INCE Plennum or "Mahling Box" (george Mahling IBM) Bacically a box frame covered by a mylar flim with a sliding gate at the rear with a pressure tap on the inlet side.

Allows you to test the fans across the /flow/pressure curve

If you request flow data most manufacturers will provide it. then all you have to do is match the pressure point.

probably only cost 100-$200 to make.

You have to watch at the 1 m that you do not get noise canceling bounce, mic/source location is important

[Stocky]

That is what I was looking for! :)

I would like to disagree that measuring the fans in free air indicates 'nothing'. It gives people (myself) some kind of comparative figures which are much better than comparing all those different manufacturers figures!

I do however understand it is not ideal; but better than nothing. I would like one of those fancy boxes mentioned, but am strapped for cash. Adding another variable to the situation would also complicate the results - although good for some ;)

I was thinking about strapping the fans to my CM Stacker as a test frame for another set of dB results - however, this rig would change over time :(

If anyone has an idea or suggestions for a basic resistance setup that could be easily implemented I'm open. I was thinking of attaching a sheet of Bounty over the intake?!

Cheers for all the advice so far folks :)

[Stocky]

It has also been suggested that a fan filter (or one on each side) would do the job. Another suggestion was to stick the fan to the centre of a rad in pull config...

(I have a PA120.3 I could do this with)

[BillA]

look into 'free air', you do not understand the experimental issues

[Ice Czar]

Air Flow Vs. Pressure Characteristics (http://www.comairrotron.com/engineering_notes_02.asp)
Parallel & Series Operation (http://www.sunon.com.tw/english/wealth/tech/tech-06.htm)
Stall of Axial Flow Fans
(http://www.comairrotron.com/engineering_notes_09.asp)
Basic Fan Laws (http://www.airturbine.com/tools/fanlaws.html?fan%20blades)
How to measure Airflow vs Pressure (http://www.sunon.com.tw/english/wealth/tech/tech-03.htm)
How to Achieve Low Noise (http://www.sunon.com.tw/english/wealth/tech/tech-07.htm)
Accoustic Noise (http://www.comairrotron.com/engineering_notes_03.asp)
EMI (http://www.comairrotron.com/engineering_notes_05.asp)
Introduction: Forced Convection Cooling (http://www.comairrotron.com/engineering_notes_01.asp)
How to select the right fan or blower (http://www.sunon.com.tw/english/wealth/tech/tech-04.htm)


suggestions for a basic resistance setup

Measuring Airflow Resistance (http://www.overclockers.com/articles750/)
actually not a very complicated test device, oh except the part where there are the calibrated nozzels, those defy DIY even if you can machine them yourself, and the part where you have to adjust your findings based on the relative humidity and barometric pressure thats fun Im sure :p

[Ice Czar]

That is what I was looking for! :)I would like to disagree that measuring the fans in free air indicates 'nothing'. It gives people (myself) some kind of comparative figures which are much better than comparing all those different manufacturers figures!

that would be exactly what you are comparing more often than not
only without the anechoic room

http://www.sunon.com.tw/english/wealth/tech/tech-07.htm

Acoustical sound measurement of SUNON fans is made in anechoic room with background noise less than 15 dBA. The measured fan is running in free air with a microphone at a distance of one meter from the fan intake.

Sound Pressure Level (SPL), which is environmentally dependent, and Sound Power Level (SPL) are defined as following :

SPL = 20¡ê P¡þPref and SWL = 10¡ê W¡þWref

where,

* P = Pressure
* Pref = A reference pressure
* W = Acoustic power of the source
* Wref = An acoustic reference power

Fan noise data is usually plotted as SPL against the octave frequency bands.

as mentioned of limited realworld value

of course some are better than others

http://www.comairrotron.com/engineering_notes_03.asp

Noise Rating Systems

Comair Rotron uses four rating methods for describing the noise levels in the fans it manufactures. The data sheets on each fan in this catalog contain noise rating in all four systems.

PSIL
The first system used is Preferred Speech Interference Level. The PSIL is determined as the arithmetic average of the sound pressure level in the three octave bans with center frequencies of 500, 1000 and 2000 Hz. This rating is a good guide to the effect of noise on spoken communications.

dBA
A second rating system is the "A weighted sound pressure level (dBA) often used by government agencies in determining compliance with such regulations as the Occupational Safety and Health Act (OSHA). The dBA rating is determined directly by a sound level meter equipped with a filtering system which de-emphasizes both the low and high frequency portions of the audible spectrum.
This measurement is recorded at a distance of 3 feet from the source.

NPEL
A third rating system is the "A" weighted sound power level reference to a 1 picowatt and expressed in Bels. This is also referred to as the Noise Power Emission Level (NEPL). NEPL was adopted by the Institute of Noise Control Engineering (INCE) as the preferred unit of measure. The INCE "Recommended Practice for Measurement of Noise Emitted by Air Moving Devices (AMDs) for Computer and Business Equipment" is a guideline for the description and control of noise emitted by components. ANSI S12.11 now includes the procedures called for in the INCE Practice. This is the latest and most technically thorough acoustic test procedure available. Comair Rotron does all acoustical testing per INCE and ANSI S12.11-1987.

Freely Suspended
The fourth rating system used is a method known as Freely Suspended. In this method a fan is suspended from springs in the middle of a Calibrated Reverberate Room. The fan is run at nominal voltage, free delivery, and at a distance of 1 meter. The sound pressure level (dBA) is recorded.
(For comparison dBA @ 1 meter + .7778 = dBA @ 3 feet).

and to further belabor and summarize the point Mike Chin of SPCR

University of British Columbia Fan Noise & Airflow Research Project (http://www.silentpcreview.com/Sections+index-req-printpage-artid-45.html) @ SPCR

With fans, despite the existence of clear, repeatable standards for measuring noise and airflow, a majority of manufacturers use microphone distances of 1-meter, 3-feet or some other distance in free space (i.e., without any impedance on the fan load) to take a single point sound pressure level measurement. Others measure the same at 30cm or 50cm. Only a few take the time to do complete sound power measurements with the fan under some kind of load that at least approaches real life applications.

This means that the manufacturers' specifications are often not directly comparable. It takes a careful, trained engineer to calculate specifications obtained from disparate techniques into comparable numbers. Even for them, it might actually be easier and certainly more accurate to take prospective fan samples and re-measure with one consistent technique.

[BillA]

"This means that the manufacturers' specifications are often not directly comparable. It takes a careful, trained engineer to calculate specifications obtained from disparate techniques into comparable numbers. Even for them, it might actually be easier and certainly more accurate to take prospective fan samples and re-measure with one consistent technique."

which is the conclusion I came to after comparing the actual fan preformance when connected to a sink or rad
fan performance is so unique that fitting a specific fan to a sink by test will yield improved performance over that having the 'best specs'

[Ice Czar]

and gets even more complicated once the fan combined with the component is actually placed in its environemnt with other components

http://www.comairrotron.com/engineering_notes_03.asp

Turbulence
Turbulence is created in the airflow stream itself. It contributes to broad band noise. Inlet and Outlet disturbances, sharp edges and bends will cause increased turbulence and noise.


System Effects on Fan Noise
System disturbances are the biggest cause of fan noise. When a fan is designed for low noise operation, it can be very sensitive to inlet and outlet disturbances caused by card guides, brackets, capacitors, transformers, cables, finger guards, filter assemblies, walls or panels, etc.;

When placing a fan in an electronic package, great care should be taken in locating components. Trial and error will be needed to determine the system's effect on noise. Different fan types will react differently in the same system. Common sense and intuition play a large role in the fan/system design.

For instance, if it is necessary to place card guides against the face of the fan for card cooling, the fan may develop a large pure tone if it is done on the inlet side; on the discharge side, the effect may be much less.

Figure 8 illustrates how one system component, finger guards, can effect noise.

http://images.dr3vil.com/upload2/eng_note_03.jpg

System Impedance
This should be reduced to the lowest possible level so that the least noise for the most airflow is obtained. The inlet and outlet ports of a cabinet can make up to between 60 and 80% of the total system impedance, which is mush too high for a low-noise result. And, if a large part of the fan's flow potential is used up by the impedance of the inlet and outlet, a larger, faster and noisier fan will be required to provide the necessary cooling.

Flow Disturbance
Obstructions to the airflow must be avoided whenever possible, especially in the critical inlet and outlet areas. When turbulent air enters the fan, noise is generated, usually in discrete tone form, that can be as mush as 10 dB higher and thus cause considerable annoyance.

Temperature Rise
Airflow is inversely proportional to allowable temperature rise with the system. Therefore, the D T limit placed on a piece of equipment will dictate to a large extent the required flow, and therefore, noise. If the temperature limit can be relaxed even a small amount, a noise reduction may result.

not to discourage you in your pursuit, but rather to make you aware of some of the variables involved so that you inturn can pass on the caveates to your adopted test proceedure in an easily understandable way to your readers
along with some tips about how they can get the most from thier choice (read the whole link) and factors that will influence the sound signiture even after its been installed (temperature gradient, dust level ect) ;)

[BillA]

lets have a shift here as this is my intended audience

1) when a fan is mounted with a shroud it is possible to get a plenum pressure indicating roughly where that specific match-up falls on that fan's PQ curve (w/unconfined/unconstrained discharge)
- anyone have an 'experimental' feel as to how shallow the shroud might be before the pressure was non-uniform (otherwise assumed)
- pitot tube considerations ? (airspeed too low to matter ?)

2) if it is accepted that the fan inlet air temp is reasonably characterized by TC msmt in each quadrant over the fan mid-blade (the Intel procedure), would the same be true for the fan/rad discharge ?
- with some other factoids could calc mass/vol air flow ?

[bobo5195]

In an effort not to make this to much of a downer.

If the fan is shrouded (by a relatively non confining shroud) and is placed far way from the source of resistance and the other side is free air then it’s fairly independent of the surroundings (except of course back pressure). This should PARTLY remove the effects of close rad distance that bill was talking about. To be more correct the fan should be 10 diameters from the exit and exit into a smooth duct expanding out from the fan at greater than 15 degrees to a large (d x 2 say) radius but I wouldn’t worry too much about that.

For sound levels just use dBA and add a few of your own thoughts. dBA is industry standard.

[BillA]

no bobo, you need to do some of this
the 10 dias have friction, how is this addressed ?
better to replicate the use conditions for 'real' results

I can run a traverse and measure the variation too, better than guessing I suppose

what do you think of the heat balance notion ? too loose ?

[Etacovda]

For sound levels just use dBA and add a few of your own thoughts. dBA is industry standard.

I'd like to see a frequency graph along with straight dBA levels, personally. Much more useful to see the characteristics of the fan noise, rather than just the straight noiselevel.

[UNDERBYTE]

I think you have to keep in mind that absolute values will not be realized in your testing.

Lacking a anechoic chamber, outside interference will affect any measurement you take. While doing some fan development I was forced to go to work at 2 am in the morning. Idling trucks a block away, air conditioners on adjacent buildings, refrigerators, flourescent lights, your breathing.....will affect the result. Additionally reflective surfaces can be a real problem.

even if you get your background down to 30dBA it will still add several dBA to your result- 38 dba can end up being 42 dba.

Best for comparative is measure something like 8 in. from the inlet as interference factors fade into the background overwhelmed by the dominate source and provide a higher degree consistancy.

Calibrated nozzels can be bought for a few hundred dollars - if you are testing a narrow range you can get by with just a couple. Some plywood and a counterblower and you have an airflow test chamber

[BillA]

"Some plywood and a counterblower and you have an airflow test chamber"
thats the stuff we need more of !!
start a thread ub, better yet jack this one

[UNDERBYTE]

I spent a day or two investigating building my own set up about 15 years ago, But ended up buying a 400 cfm set up with a large contract I got.

Most fan manufacturers bulid their own like the one in the link below, a box, some nozzels, couple of flow straightners, pressure taps, manometers, blast gate(to vary airflow) counter blower. Get ahold of the AMCA specs it will just take a day for you to figure out how to build it. Pretty simple actually, probably build it in a day or two for a couple of grand or less

I have seen homemade flow chambers washing machine sized to garage sized for measuring 40,000 cfm

Nozzels at the time were 300 to $400 USD apiece

I prefer the liquid manometers, you get more of a physical sense when the fan starts slip or when your flow test has flow anomaly over the digital ones

http://www.torringtonresearch.com/testequipment.html#tests

[UNDERBYTE]

I spent a day or two investigating building my own set up about 15 years ago, But ended up buying a 400 cfm set up with a large contract I got.

Most fan manufacturers bulid their own like the one in the link below, a box, some nozzels, couple of flow straightners, pressure taps, manometers, blast gate(to vary airflow) counter blower. Get ahold of the AMCA specs it will just take a day for you to figure out how to build it. Pretty simple actually, probably build it in a day or two for a couple of grand or less

I have seen homemade flow chambers washing machine sized to garage sized for measuring 40,000 cfm

Nozzels at the time were 300 to $400 USD apiece

I prefer the liquid manometers, you get more of a physical sense when the fan starts slip or when your flow test has flow anomaly over the digital ones

http://www.torringtonresearch.com/testequipment.html#tests

[BillA]

thanks
did/do you condition the air temp/moisture ? or just record it ?

comments on post#20 ?

[UNDERBYTE]

If you are at some elevation like Denver I would correct for that, also temp and barometric (radio shack meter or local weather internet source) you can do wet/dry bulb humidity as an exercise but generally I do not bother as impact is usally minimal. Although it it is good to start that way to get a feel for the process

[UNDERBYTE]

Re post # 20

On some airconditioning projects I worked on I found that condensers/radiators can act sometimes like that highspeed Delta fan with the downstream tuning vanes and increase/decrease flow through the condenser. PQ curve generally only puts you in the ballpark. OK for comparative devlopment to a point , then I confirmed/tweaked design by leasing Torrington Research's or EBM/pabst flow chambers for final evaluation on fans that my set up was not large enough for.

I never really get "to the bank" numbers until I test with a AMCA SET UP. Bootstapping airflow test set ups in my case usally ended being a hodgepodge. Too much wasted time trying to figure out whether the numbers were good or not.

Time is better spent putting together a reliable test set up rather than customizing each new test and then having to validate it. It takes me all of about 5 min to run a full PQ curve and less than a min. to take a system point like you would on a static radiator fan test. After all what is your engineering time worth? Mine is several hundred per hour:)

[BillA]

"Mine is several hundred per hour"
lol, Liar Gabe put my notions of such to rest; my 'effective pay rate' considering hours worked was <$10/hr
patsy BillA

[UNDERBYTE]

I quit taking consulting contracts several years ago although the money seemed good, the benchmark was always a strain to hit. After hours worked effective pay did not justify the labor.

there are better ways to make money

[Ls7corvete]

IDK about all this but I would like to see the delta EFB1212LE and the new coolermaster alum fan tested.

[bobo5195]

I am assuming we are talking about the ASME (acma?) spec here. I pointed out in another thread (I think it was at spcr) that building a test chamber for one of these is relatively easy and would give quite good results but someone said no for some reason. There are issues with low flows and measurement accuracy but ghetto/diy-able liquid in glass manometers are very good at measuring flows (as underbyte who probably knows a lot more about these things that i do) they do give nice consistent results. I’m not sure if a restriction might be better to create back pressure, just to save on cost and complexity.

Air properties might be a factor bill if your after your usual rigorousness. It’s a good statistic to have at least as it shows if a damp and cool basement is doing anything for example (thinking mike C at spcr here), although the results are only likely to have a small change. If your measuring to 2 sf they are likely to be just about noticeable (max 5% error).

10 dias have a small amount of friction which is known and the air flow distribution at the end is known as well, so its an error that can be factored out. More importantly the 10dias is a for a general flow a fan flow could well only need of the order of 1 dia.

Heat balance could work, indeed this is what thermal anemometers are, but you need a good test rig to confirm how the rad performs as well and looking at the variables involved it is too hard to get good numbers compared to other methods. It may well be non linear results as well which is annoying.

I disagree with testing fans at close distances to rads or obstructions as the variables involved explode ******ds. In reality you could never test all situations and variations between similar (same manufacturing line) fans would be a factor as well.

Im currently doing contracts for abit over $100 an hour, while still at uni but when you work out all the additional work its more like minimum wage and they will be feeling the force of my lawyer if they don’t pay me soon!

[BillA]

and I had hoped a technical field might buffer me from economics, fat f***ing chance that

re testing fan/rad assys, not so many combos really
base (for heater cores only today) is fan on fins
2ed is ~1/4" standoff (built into all 'computer' rads)
3ed is greater than 1/4" (no measurable dissipation increase however, why bother ?)

some w/o data may theoretically contest #3, but I've confirmed such now with 2 separate benches and numerous rads
the convential rot is 1/2 the fan dia, but also at that distance I can measure no increase over 1/4" (our little muffin fans ?)

my question was: if measuring the differential air pressure (in 1/4" plenum to ambient/rad backside), will that nominally equate to a point on the fan's PQ curve ?

[UNDERBYTE]

$$$$my question was: if measuring the differential air pressure (in 1/4" plenum to ambient/rad backside), will that nominally equate to a point on the fan's PQ curve ?
Today 09:45 AM$$$$


Generally they only match about half the time ( within 5% or less) the other half of the time +/- 5-10% Rarely do I get a spot on match from a system/PQ curve

occaisionally I have had radiator fin configurations that straighten the flow in an optimal sense and in so doing actually increase flow as much as 10% and others as much as 10% less than the system point.

When you add a radiator to a fan, in a sense it becomes a diff. fan with pos-neg. or minimal effect.

Probably close enough -

[bobo5195]

underbyte - doesn't that go away if you push with the fan instead of pulling through the radiator . The radiator then acting as a lamina flow guide before air is pushed into the fan.

The procedure has a number of things going for it, providing a good rad can be found for testing and the shroud was well sealed with a some nice liquid manometers then this could be an excellent test rig. Within 5% is good enough for me and repeated tests / a few different rads could help things.

It has the major advantage that most of the stuff is readily available in the community and is cheap (no digital meters, a lot of stuff that ppl have hanging around). Most importantly it’s measuring real life, exactly how someone would run a rad with a shroud.

You should try at longer lengths bill just to confirm you could well just be hitting a resonance point caused by the waterfronts coming of the fan. ½ dia seems to close to me, but I could well be wrong.

[BillA]

ok, I'll do it
should be getting a 0-40"WC dP xmtr which I'll recal to 0-5"WC this week
get some small brass tubing, thinking it run into the plenum under a fan motor strut
experiment with the tube end to avoid a pitot tube effect I suppose

the atmospheric pressure sensor would not cal so I am waiting for its replacement
capacitive humidity sensor ok, eventually should have 'corrected' air data

[bobo5195]

careful do you know exact dp vs flow for a rad and you need to be very careful with the manometer entrance. Idealy sheilding it some how as all kinds of flow directions will be coming of the fan.

Need a duct on the end of the rad to help measure dp across it as well.

[BillA]

eh ?
for the liquid side, sure; air side about zip, never will 'know' the mass/volume flow
no, rad exit to air (as is presumably done); pressure in area of unconstrained exit flow is I think sufficient for a differential pressure reading

this dP can be had with some precision; how sensitive such is to the tip configuration and placement needs to be assessed, I agree
(same readings from several similar positions = 'ok' tip effect ?)

when I get some data I'll send it round

[UNDERBYTE]

BillA,

Tis the season- Bill if you would like I could run a system resistance curve and a couple of PQ curves on my Flow chamber to give you a baseline to work your set up.

Normally I get several huindreds of dollars an hour for this, :D but if you pay for shipping I will donate an hour or two to the cause.

I test to AMCA 210-85 and am accurate up to 400 cfm

[BillA]

aiiiii
super offer ub
let me get my hardware straight, and sort out a useful matrix
a bare rad, then with a couple of fans ?
possible to get the 2 fans at 3 voltages ?
a better method ?

(An aside to all; procooling, being on the extremest fringe of WCing, has an extreme audience as well - many of whom have knowledge, experience, and resources in exactly those areas of interest to us. We should strive to make the contribution of services an enjoyable experience.)

[Marci]

Someone gag me... afore I volunteer a set of PA series rads...

[BillA]

not really for data, is a means (hopefully) to cross-correlate to get a nominal CFM (or flow resistance vs. ?) on a bench w/o air flow measurement capability
a single rad and fan(s) are a PQ reference, dissipation is apart
as a reference it is the specific combination of those actual pieces
(I see ~5% variation in performance between the 'same' rads, several mfgrs' products considered - all with the same fan @12.00 ±0.01 VDC)

[UNDERBYTE]

aiiiii
super offer ub
let me get my hardware straight, and sort out a useful matrix
a bare rad, then with a couple of fans ?
possible to get the 2 fans at 3 voltages ?
a better method ?



Bare rad system curve ok

Couple of fans ok

can run full 6-12 volt curves if you like-or single system points at different V

can run shroud variations(Distance?) on single point say 12V ?

[BillA]

let me first run my curves, I need some plenum pressure data to 'look at'
sounds great
say system points at 3 voltages (?)
skip the shroud, at ~1/4" the dissipation is optimized (by test)

thinking out loud . . . .
2 general rad cases; higher airflow resistance (2 core) and lower (single core)
- 2 core selected for performance, more powerful fan
- single core for lower noise, less powerful fan

is either rad configuration 'better' than the other ? (to establish an air flow reference)
seems that the air flow pressure range would be greater with the 2 core/more powerful fan combo
?

I should add

the actual rad/fan(s) combo could be preserved and passed around between testers as useful for cross referencing benches

not too many doing rad testing just now though

[gmat]

yep 3 voltages, 12V / 7V / 5V as they are the common data points used on SPCR and other sites to measure noise. So by crossing your flow data with the existing noise data we'll be able to assess a performance / noise ratio. Sounds promising.

[BillA]

can o'worms now, fan(s) ?
2 max
higher and lower, with 30% overlap of rated CFM ?

specific models helpful

[bobo5195]

Sorry bill I was thinking about something else. I’ll post something when I am feeling better (ie not had 1 hours sleep, don’t have a lecture in 2 hours and haven’t been drinking absinth and having various other naughty stuff  ).

Looks good I’ll see what the results are like. I’m sure Les will build you a model.

Fans are indeed tricky, my mind is not totally reliable this morning but CFM should be proportional to voltage cubed I think.

I agree with testing against SPCR data as they are ultimately the benchmark in this area and we should try and beat their data. The more data points the better though.

[gmat]

2 fans sounds good
the usual suspects will be fine - Panaflo L1, Papst 4412, Noiseblocker, etc.

[UNDERBYTE]

let me first run my curves, I need some plenum pressure data to 'look at'
sounds great
say system points at 3 voltages (?)
skip the shroud, at ~1/4" the dissipation is optimized (by test)

thinking out loud . . . .
2 general rad cases; higher airflow resistance (2 core) and lower (single core)
- 2 core selected for performance, more powerful fan
- single core for lower noise, less powerful fan

is either rad configuration 'better' than the other ? (to establish an air flow reference)
seems that the air flow pressure range would be greater with the 2 core/more powerful fan combo


2 rad cases fine

I assume fans are 120mm X 25MM?

When I do fan comparisons on homologous fans I like test them @ equal RPM vs. Volts. method, if there are diff. in performance it is quickly apparent.

[BillA]

been hung up waiting for a 4"WC dP unit, which is now being caled
added a pitot tube to each fan as in the images, be interesting to see the correlation

the Nexus is 120x25, the Panaflo is a 38, is this a problem ?

trying to figure out what single core rad to use (it will not be Swiftech's)

[TerraMex]

suggest 6 V also -> limit for a good number of fans (AFAIK), so four point, instead of three.
(yes, admittedly three will be very close 7/6/5 , but isn't that the point?)

[BillA]

the Nexus is ok at 6V, the Panaflo FBA12G12M does fine at 5V (below spec)