watercooling + paste

Halfgaar wrote:
David Maynard wrote:

I didn't have one either, till recently. I had always thought one would
be 'nice' but just never forked over for one. Now I can't imagine why I
waited so long.

I got my "rotary tool" from Sears during a sale but these people have an
inexpensive job (plus other cheap tools) with some nifty accessories.

http://www.softwareandstuff.com/tol_elerotkit.html

I don't know how good it is but 30 bucks for all of that is an
impressive deal. Figure on spending another $10 to $20 for various bits,
cutting discs, etc, depending on what projects you dream up. (Sears
stuff should fit, and is convenient, as they all use the 1/8" arbor)


Something like it would be convient, but I don't really need it all that
often. And software and stuff probably don't delive outside the US (and I
don't like ordering things online )

They probably don't. Too bad because they have interesting deals from
time to time.

Halfgaar

Nick M V Salmon wrote:
"Halfgaar" wrote

David Maynard wrote:

Just a moment there. I didn't say one or the other was 'better'. I was
talking about how ducting the fan worked and that's there's more to it
than simply putting the fan in either the front or back.

Sorry, I misinterpreted. I can't really find who said it, but someone did.


[UK[_Nick wrote it, ie. me, sucking is better - assuming the same
temperature inlet air. I'll explain the reason for it again too; Air spins
outward from the outlet of a fan - if it is blowing through a radiator then
the vast majority of the air travels through the outer edges of the radiator
alone. If a fan is sucking through a radiator then you get a roughly equal
amount of air travelling through the whole area of the radiator.

That is true but the fly in the ointment is that axial fans can't pull
against pressure as well as they can push into it (which isn't much to
begin with). The upshot is that, depending on how much restriction there
is, the air distribution will probably be better but the airflow will be
less.

If you just 'feel' to compare the air flowing through a radiator when
sucking or blowing then you'll get the impression there's a stronger draft
when blowing because there _is_ a stronger draft, but it's all concentrated
at the outer edges of the radiator.

I've tried it both ways and 'sucking' seems to win BUT, by far the more
important point is - how hot is the inlet air..? A radiator can only
radiate into colder air thus air already pre-heated by the rest of the
components in a computer, or coming from a relatively hot place in a room,
isn't much use...

Ciao...

[UK]_Nick...

Halfgaar wrote:
Halfgaar wrote:

Before I close this thread, I'd like to point out something to you Nick:

You can find this on the Innovatak (manufacturer of my radiator) site (the
site is german, this is world.altavista.com'ed):

"The fine lamination of the radiator provides for an optimal heat emission
to the cooling air, without obstructing however the air flow substantially.
Further the air flow of the fan is optimally used by the integrated
Fanhouse, since by this pre-chamber the whole surface of the radiator is
flowed around by the cooling air. In addition this measure contributes also
to the reduction of flow noises - the radiator is very quiet therefore."

This says that the fanduct is meant for spreading out the airflow over the
entire radiator surface, preventing a dead spot.
Any comments on this ?

The noise will be less because the fan blades are further from the
irregular radiator surface and so there will be less air beat against it.

If it is, in fact, distributing the air across the radiator surface then
it would be due to pressure build up on the radiator surface (periphery
where the duct contacts it) causing some air to flow toward the lower
pressure area in the center and then through the radiator there.
However, that (back) pressure is also going to reduce the fan's total
airflow.

What they're describing resembles an air plenum in front of the radiator
with the fan 'pressurizing' it and the plenum pressure then causing air
to flow through the radiator. That works best, though, when the fan is
smaller than the radiator so that the airflow doesn't have to make
drastic direction changes.



Halfgaar

David Maynard wrote:

That is true but the fly in the ointment is that axial fans can't pull
against pressure as well as they can push into it (which isn't much to
begin with). The upshot is that, depending on how much restriction there
is, the air distribution will probably be better but the airflow will be
less.

I think I'll call an end to this thread . I've gotten some usefull advise.
And I made some changes. Then fan is now sucking in air from outside the
case trough a 1cm long fanduct, blowing it through the radiator. I've
tested this configuration before, but without the intake fanduct. The
intake fanduct seems to help both in decreasing noise as well as increasing
airflow. The intake fan pressed directly against the metal intake filter is
apparently a bad idea. These are my temps after hours of use (mostly Idle
BTW):

Rad. Fan: 1454 RPM (min = 998 RPM, div = 8)
CPU Temp: +41.6°C (limit = +63°C, hysteresis = +60°C)
Sys Temp: +32.1°C (limit = +41°C, hysteresis = +40°C)

The best I've had with the current room temp (25 degrees C).

The radiator feels quite cold, so I guess I should try some different
thermal paste (the paste question was infact the start of this thread....,
whether different paste would make a difference....)

Anyway, thanks to everybody for your input.

Halfgaar
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