Some radiator fan questions.

Since87 · 11-24-2002, 09:50 PM

I've got a somewhat large thin heatercore. The airflow region measures 9.5" X 5.75" X 1.2". I've got two 120mm Papst 4312L fans I plan on running side by side.

Does it make much difference (in noise or airflow) whether the fans are pushing air through the radiator or pulling air through the radiator?

I would guess that, as with pumps, restricting the inlet is to be avoided if possible, but that's purely a guess.

I read somewhere (I think it was Cathar writing) that giving each fan it's own shroud was fairly beneficial.

Would there be any value in partioning the airflow path further?
(Say quartering each fan for eight seperate shrouded regions.) Or, is the main benefit only in seperating the airflow at the line between the two fans, because the fan blades are moving in opposite directions along that edge?

Aardil · 11-25-2002, 02:16 AM

The main reason for using fan shrouds is this:

the middle of your fan ( where the motor is ) makes a dead spot in the middle of your Rad. by using a shroud you effectively reduce the dead spot because the fan is a bit farther away from the Rad.
Pretty straight forward if you think about it. My choice is anytime I have room I would use a shroud.
As far as further dividing the shroud into quarters . I do not see where there would be any benifit, in fact I believe it would hurt more than help. I dont have any data to back this up, just my mind saying nope . I could be wrong but I dont think so.
As far as optimal distance from fan, I really dont know.
Hope this helped some
Aardil

MadDogMe · 11-25-2002, 03:46 AM

A shroud divided up into sectors is called a 'Plenum Chamber' if I'm correct, and is very good for gaurenteeing equal flow over ALL areas...

I'll always have my fans drawing air through the rads...

I put a partition between my two fans and I still get a 'resonance' at full speed...

gmat · 11-25-2002, 04:40 AM

- use shrouds, everytime
- try to partition to avoid resonance (or reduce it to a minimum) and conflicting vortices
- don't partition a single fan, it will kill flow
- tube-axial fans are usually better at 'pulling' than at 'pushing'. Some high-end fans (papst..) with very close tolerances would be rather indifferent though.

utabintarbo · 11-25-2002, 07:42 AM

Check HERE for some good info on fan shrouding, etc.

Bob

airspirit · 11-25-2002, 01:15 PM

If you are just putting fans on one side, you should pull every time. It is easier for a low pressure fan to pull than push. Just shroud them about an inch or two from the radiator for maximum efficiency.

Since87 · 11-25-2002, 06:53 PM

Thanks guys.

Especially utabintarbo, for the link.

11-24-2002, 09:50 PM	#1
Since87 Pro/Guru - Uber Mod Join Date: Sep 2002 Location: Indiana Posts: 834	Some radiator fan questions. I've got a somewhat large thin heatercore. The airflow region measures 9.5" X 5.75" X 1.2". I've got two 120mm Papst 4312L fans I plan on running side by side. Does it make much difference (in noise or airflow) whether the fans are pushing air through the radiator or pulling air through the radiator? I would guess that, as with pumps, restricting the inlet is to be avoided if possible, but that's purely a guess. I read somewhere (I think it was Cathar writing) that giving each fan it's own shroud was fairly beneficial. Would there be any value in partioning the airflow path further? (Say quartering each fan for eight seperate shrouded regions.) Or, is the main benefit only in seperating the airflow at the line between the two fans, because the fan blades are moving in opposite directions along that edge?

11-25-2002, 07:42 AM	#5
utabintarbo Cooling Savant Join Date: Jul 2002 Location: Sterling Hts., MI Posts: 496	Check HERE for some good info on fan shrouding, etc. Bob __________________ Sarcasm is yet another of the free services we offer!

11-25-2002, 01:15 PM	#6
airspirit Been /.'d... have you? Join Date: Jul 2002 Location: Moscow, ID Posts: 1,986	If you are just putting fans on one side, you should pull every time. It is easier for a low pressure fan to pull than push. Just shroud them about an inch or two from the radiator for maximum efficiency. __________________ #!/bin/sh {who;} {last;} {pause;} {grep;} {touch;} {unzip;} mount /dev/girl -t {wet;} {fsck;} {fsck;} {fsck;} {fsck;} echo yes yes yes {yes;} umount {/dev/girl;zip;} rm -rf {wet.spot;} {sleep;} finger: permission denied

11-25-2002, 02:16 AM	#2
Aardil Cooling Savant Join Date: Oct 2002 Location: Louisiana Posts: 174	The main reason for using fan shrouds is this: the middle of your fan ( where the motor is ) makes a dead spot in the middle of your Rad. by using a shroud you effectively reduce the dead spot because the fan is a bit farther away from the Rad. Pretty straight forward if you think about it. My choice is anytime I have room I would use a shroud. As far as further dividing the shroud into quarters . I do not see where there would be any benifit, in fact I believe it would hurt more than help. I dont have any data to back this up, just my mind saying nope . I could be wrong but I dont think so. As far as optimal distance from fan, I really dont know. Hope this helped some Aardil

11-25-2002, 03:46 AM	#3
MadDogMe Thermophile Join Date: Aug 2002 Location: Just shut up ;) ... Posts: 1,068	A shroud divided up into sectors is called a 'Plenum Chamber' if I'm correct, and is very good for gaurenteeing equal flow over ALL areas... I'll always have my fans drawing air through the rads... I put a partition between my two fans and I still get a 'resonance' at full speed...

11-25-2002, 04:40 AM	#4
gmat Thermophile Join Date: Mar 2001 Location: France Posts: 1,221	- use shrouds, everytime - try to partition to avoid resonance (or reduce it to a minimum) and conflicting vortices - don't partition a single fan, it will kill flow - tube-axial fans are usually better at 'pulling' than at 'pushing'. Some high-end fans (papst..) with very close tolerances would be rather indifferent though.

11-25-2002, 06:53 PM	#7
Since87 Pro/Guru - Uber Mod Join Date: Sep 2002 Location: Indiana Posts: 834	Thanks guys. Especially utabintarbo, for the link.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)