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General Liquid/Water Cooling Discussion For discussion about Full Cooling System kits, or general cooling topics. Keep specific cooling items like pumps, radiators, etc... in their specific forums.

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Unread 05-10-2004, 12:29 AM   #126
Cathar
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Quote:
Originally Posted by Groth
Well, if you get swirling really fast, centrifugal force opens up a partial vacuum in the center, which means more of your water molecules are closer to the metal, plus a small amount phase change fun. Of course you still have the overall goodness of higher pressure and higher velocity at your boundary layer.
No vacuums - we don't want the water to cavitate leaving dry spots on the metal - besides - the pumping power required to effectuate a phase-change on water in these conditions is significantly greater than what hobbyist pumps can achieve.

Last edited by Cathar; 05-10-2004 at 12:54 AM.
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Unread 05-10-2004, 01:06 AM   #127
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Quote:
Originally Posted by Cathar
No vacuums
Ahh, yer no fun!
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Unread 05-10-2004, 05:47 AM   #128
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Originally Posted by AngryAlpaca
Ooh! I know! Mini spirals! (Slaps self, so others don't have to) jlrii: If you're forcing the spiral, it's irrelevant.
Twas' but a joke
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Unread 05-10-2004, 06:51 PM   #129
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I should have realized that from a mile off. We want vacuums! Hmm... I think meteors are more destructive than most other things, as destruction is much larger. Just because they are more rare does not make them less destructive. However, I cannot see how this would be applied to watercooling (little copper pellets shooting at high speeds?)

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Unread 05-10-2004, 09:13 PM   #130
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Originally Posted by AngryAlpaca
I should have realized that from a mile off. We want vacuums! Hmm... I think meteors are more destructive than most other things, as destruction is much larger. Just because they are more rare does not make them less destructive. However, I cannot see how this would be applied to watercooling (little copper pellets shooting at high speeds?)
Iread some where about experiments going on trying to increase the heat carrying capacity by adding copper nano-particals
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Unread 05-10-2004, 09:40 PM   #131
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Yeah, those are some cool experiments. The suspended copper would work especially well with a whirlpool/tornado block -- the centrifugal forces would push the copper to the outside and into the boundary layer where you want it. The trick is to use a low enough concentration so that you don't have so much copper accumulate such that you end up with a zone of shear-thickening fluid lining your block's passages.
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Unread 05-10-2004, 09:46 PM   #132
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Quote:
Originally Posted by Groth
Yeah, those are some cool experiments. The suspended copper would work especially well with a whirlpool/tornado block -- the centrifugal forces would push the copper to the outside and into the boundary layer where you want it. The trick is to use a low enough concentration so that you don't have so much copper accumulate such that you end up with a zone of shear-thickening fluid lining your block's passages.
and this would be done how ?
you could make the sg the same as copper, but then the viscosity goes to hell, . . . . .
however there is a solution, patented of course
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Unread 05-10-2004, 10:01 PM   #133
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Of course there's a solution. There's always a solution, and it's usually found by someone outside of PC watercooling. Patented by whom? I personally think that instead of focussing on crack-headed-copper-suspended-in-some-sort-of-liquid solutions, we should be working on the block designs, like Cathar is. It seems that everyone everywhere has looked for a fluid better than water, but I don't know of anyone finding any. sg means what? I looked it up and I found "specific heat" but I'm not sure how that's relevant, as copper doesn't have the greatest of that.
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Unread 05-10-2004, 10:51 PM   #134
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sg = specific gravity

I wouldn't mess with viscosity or specific gravity. I'd experimently determine a curve for benefit vs copper amount for my system.

What patent?
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Unread 05-10-2004, 11:03 PM   #135
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So density as opposed to water, as I understand it? What is the point of making the liquid the same density of copper? Wouldn't the point of using copper be to utilize the high conduction, and not worry about corrosion?
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Unread 05-10-2004, 11:19 PM   #136
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A higher specific gravity fluid would decrease the tendency of the copper to be centrifugally separated out of the fluid in the highly swirly sections -- you want some copper suspended in the boundary layer, not a layer of powdered copper coating your heat transfer surfaces. Note: this is only an issue for the theoretical fast spinning tornado blocks.
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Unread 05-10-2004, 11:44 PM   #137
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aw, both headed in the wrong direction
come on now:
so if the medium's sg is the same, then . . . . .
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Unread 05-11-2004, 12:03 AM   #138
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Quote:
Originally Posted by unregistered
aw, both headed in the wrong direction
come on now
I'd head over to your house and give you a swift kick in the rear for being so annoyingly abstruse, except that I do the same damn thing.

I haven't the faintest idea where you're trying to lead me, more hints please.
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Unread 05-11-2004, 07:20 AM   #139
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Quote:
Originally Posted by unregistered
and this would be done how ?
you could make the sg the same as copper, but then the viscosity goes to hell, . . . . .
however there is a solution, patented of course
Ahhtook me 15 min to find a relevent article...HERE ...$$$??? says up to a 40% increase in thermal conductivity HERE

Last edited by jlrii; 05-11-2004 at 07:33 AM.
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Unread 05-11-2004, 09:27 AM   #140
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Quote:
so if the medium's sg is the same, then . . . . .
Then what? You've got a fluid that can move through your tubing, but probably sucks at removing heat?
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Unread 05-11-2004, 09:50 AM   #141
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Quote:
Originally Posted by jlrii
Ahhtook me 15 min to find a relevent article...HERE ...$$$??? says up to a 40% increase in thermal conductivity HERE
Note that the 40% improvement was the BIGGEST improvement seen, and this was observed when using ethylene glycol as a base, not water.

As I understand it, this technology is more suited to providing lesser coolants with thermal characteristics closer to that of water without many of water's inherant problems, corrosion for example.

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Unread 05-11-2004, 09:56 AM   #142
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spoon fed, eh ?

close jlrii
the 'trick' is th make the cu into nanospheres, the effective sg of which can be mfgd as desired
- problem is that I could not find a commercial source of cu nanospheres

work wonderfully BTW, their impingment destroys the boundary layer
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Unread 05-11-2004, 10:43 AM   #143
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effective sg? Yeesh! Must be a engineering term, I don't know any self-respecting physicist that would be caught dead with such a kludge. And why would you think I had larger particles in mind?

BTW, if they work through impingement destroying the boundary layer, why would all the researchers measure the thermal conductivity with a hot-wire test? No boundary layer in a still fluid...

Lead astray.
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Unread 05-11-2004, 12:24 PM   #144
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not being a self-respecting physist, I take many such liberties
and was at a loss as to how to preclude the nanospheres assessment in air, rather than water, yea sg = 1

will look for the papers (3-4 mos back, difficult)
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Unread 05-11-2004, 12:52 PM   #145
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Quote:
Originally Posted by unregistered
spoon fed, eh ?

close jlrii
the 'trick' is th make the cu into nanospheres, the effective sg of which can be mfgd as desired
- problem is that I could not find a commercial source of cu nanospheres

work wonderfully BTW, their impingment destroys the boundary layer

Yeah the metorite comment above reminded me of the nano fluid stuff
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Unread 05-11-2004, 06:07 PM   #146
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"As I understand it, this technology is more suited to providing lesser coolants with thermal characteristics closer to that of water without many of water's inherant problems, corrosion for example."

I believe this refers to the thermal conductivity of straight water with nanoparticles. It references paticals of both Al and Cu.

Quote:
"For example, the use of A12O3particles ≈13nm in diameter at 4.3% volume fraction increased the thermal conductivity of water under stationary conditions by 30% [6].Use of somewhat larger particles (≈40 nm in diameter) only led to an increase of less than ≈10% at the same particle volume fraction [5]; more in accord with theoretical predictions[7]. An even greater enhancement was recently reported for Cu nanofluids, where just a 0.3% volume fraction of 10 nm Cu nanopar-ticles led to an increase of up to 40% in thermal conductivity [8], a result that is more than an order of magnitude above the increase predicted by macroscopic theory. Currently, the origin of such remarkable increases in the thermal conductivity of nanofluids eludes theoretical understanding."

It doesnt mention water in motion
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Unread 05-11-2004, 10:57 PM   #147
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Yes spoon fed is awesome. I didn't realize what the copper actually did for cooling.
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Unread 05-11-2004, 11:15 PM   #148
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Well the plans for the refined prototype are complete. Unlikely that I'll make too many changes after this next prototype.

My goal with the refined prototype is to exceed the SS across the entire test flow-rate range (2-10LPM), and exceed the XS at anything above 4LPM. The XS has quite phenomenal low-flow performance so I won't set my aim quite that high, but if I do beat it, I'll be a happy person.
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Unread 05-12-2004, 12:12 AM   #149
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What kind of pressure drop does the XS have? All this talk of flows is kind of useless without it. For all we know, the X-flow could have the best performance at 10LPM (we just can't get to that flow... 37.5 feet... Hehe)
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Unread 05-12-2004, 12:50 AM   #150
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The XS has a moderate-high pressure drop, at about 6mH2O at 10LPM.

An Iwaki MD30-RZ can drive the XS at 10LPM. A Swiftech MCP600 at just under 6LPM. A Laing D4 at ~7LPM at 12V, or ~9.5LPM at 16V. An Eheim 1250 at around 5.5LPM. An Eheim 1048 at 4LPM. That's not counting other system resistances, which given the significance of the XS in the loop, have a fairly minimal impact on those flow-rates listed. As you can see, there exists plenty of options to get the block up to the upper end of the flow rate ranges that I test at, and indeed, that is how I manage to test at those flow rates.

I already know what the PD of the newer P2 refinement will be ahead of time, but I may change it depending on the outcome of some experiments with it.

Hmm, I wonder if Dyson will be mad about the block?

Last edited by Cathar; 05-12-2004 at 03:28 AM.
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