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Turbulence - How do you eat yours?

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G33k

Member
Joined
Mar 1, 2002
Location
Bristol [UK]
I'm sure most of you guys are aware now (even if you don't water-cool stuff yourself) that there are a few key areas to making a successful water-block; Surface area, Turbulence, Volume and Flow Rate.

There's been a lot of discussion on methods of creating turbulence and the most recent craze seems to be Spirals of some sort or another.

One thing that seems to have been over-looked it the whirlpool design which was one of the first commercially available! Can't remember who it was that made it though (anyone remember?). This is my humble creation :


[Click the pics to enlarge]

The water comes in at the base (next to the CPU) and catches the side of the block. It swirls round pretty damn fast, believe me! I'm only using a 1046 too :eek:. Actually, the block above is one I created for a mate - I use a very similar Slot-A version.

Before I added the pins, the whirpool created was enough to hold air in the outlet of the block :


[Click the pic to enlarge]

I've a couple more ideas to improve this design, but even now it performs very nicely - my CPU is normally sitting at about 10 degrees (Celcius) over the coolant temperature :D. This is a 750Mhz (Slot - remember those? ;)) Athlon @ 963, running at 2.05v (1.6 is default).

So my question to you guys is : How have you made your water-blocks and what measures have you taken to increase turbulence? What was your design-angle - high flow rates? high surface area? Low weight/cost?
 
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juliendogg

Member
Joined
Nov 29, 2001
Location
NC, USA
at any rate, i dig the block! put a silver base on it with silver pins sticking up into the water bonded to the silver base and you'd get excellent heat transfer from the pins.


nice work g33k.

i'm interested in seeing your new ideas
 

Miss_Man

Registered
Joined
Dec 26, 2000
Turbulence?
Comes from free-hand milling, dual inlets to a single outlet, and a big pump for that high flow. :)
2b.jpg


High surface area?
My watersink approach.
block1.jpg


45.jpg
 

MiseryQ

Member
Joined
Jan 10, 2002
I think Les56 is right...

Turbulence would be irregular flow...
What you have is laminar flow...

The way I see it's six of one half a dozen of the other... Both should work by slowing the the flow of water long enough to transfer heat...

One good point to laminar flow is that turbulence causes restriction...
 
OP
G

G33k

Member
Joined
Mar 1, 2002
Location
Bristol [UK]
If you look at the second image, you'll notice that the pins extend right across the base of the block. The water enters right in front of these so it's churned up. Each of the pins adds turbulence to the water and because it is spinning at such high speeds, I would imagine it's probably quite turbulant in there?

I'm by no means an expert, but from what I've read, I believe I'm correct. If you believe otherwise, by please DO correct me! :)

Les56 : Reading that article, one of the firsts posts points out that at speeds greater tham 20mL/Sec you get turbulent flow. There is DEFINITELY turbulent flow, what I'm interested in is whether my block would perform close to a Maze2... Anyone wanna lend me one for testing? :D
 
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G33k

Member
Joined
Mar 1, 2002
Location
Bristol [UK]
MiseryQ said:
I think Les56 is right...

Turbulence would be irregular flow...
What you have is laminar flow...

The way I see it's six of one half a dozen of the other... Both should work by slowing the the flow of water long enough to transfer heat...

One good point to laminar flow is that turbulence causes restriction...

I don't think that turbulance works by slowing the water down, long enough to heat it. From what I understand, turbulent flow reduces the boundary layer (very thin layer of water next to the edge of the block).

Low flow / less turbulence increases the boundary layer.

High flow / more turbulence decreases the size of the boundary layer which means the hot surfaces in contact with the water are cooler, because the coolest coolant is closer to the hot surface... I suspect I may be a way off on that last point - BillA / Aesik, feel free to flame (read correct) me ;)
 

res0r9lm

Member
Joined
Dec 14, 2001
Location
florida
G33k said:


I don't think that turbulance works by slowing the water down, long enough to heat it. From what I understand, turbulent flow reduces the boundary layer (very thin layer of water next to the edge of the block).

Low flow / less turbulence increases the boundary layer.

High flow / more turbulence decreases the size of the boundary layer which means the hot surfaces in contact with the water are cooler, because the coolest coolant is closer to the hot surface... I suspect I may be a way off on that last point - BillA / Aesik, feel free to flame (read correct) me ;)

turbulance are effective b/c they increasing boundry layer flow. I know it's pretty much what you have already stated just confirming it to be right.
 

Les56

Member
Joined
May 31, 2001
Location
Wigan UK
G33k said:


Les56 : Reading that article, one of the firsts posts points out that at speeds greater tham 20mL/Sec you get turbulent flow. There is DEFINITELY turbulent flow, what I'm interested in is whether my block would perform close to a Maze2... Anyone wanna lend me one for testing? :D

Quite.Thewater entering through a 7mm nozzle at rate greater than 72 L /min(20mL/sec) may well be turbulent but is this turbulence destroyed in the whirlpool?. I don't know.
 

juliendogg

Member
Joined
Nov 29, 2001
Location
NC, USA
the way the pins are all protruding into the flow, perpindicular to the "laminar flow" they should be diverting water and causing turbulance.


what were your temps with it and what other equipment, type setup, were you using?
 
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G33k

Member
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Mar 1, 2002
Location
Bristol [UK]
Julien Dogg : Temps were normally about 10 (15 under prime95) degrees over the coolant entering the block. It's been a while since I've been able to check temps though as I broke my monitoring device :(

res0r9lm : Cheers m8 :)

Miss_man : I like the water-sink idea, that looks like it ought to perform pretty well. What sort of temps (relative to coolant) do you get and what do you run those blocks on (what chip?)?
 

Miss_Man

Registered
Joined
Dec 26, 2000
I have not measured block temperature before. It is used to cool 2 172 watt peltiers and a Thunderbird, and its doing a pretty good job I must say. Doesn't even get overwhelmed when I turn both voltages to 22V.
 

SNIPER1M

Registered
Joined
Feb 28, 2002
Location
Fargo, ND area
Not to drop a bomb on you, but discussions on laminar flow within the waterblock is stuff ad men write to sell stuff. I guarantee that no waterblock design has a problem in this area. Laminar flow exists only in situations where a fluid travels in straight uninterrupted flows. Any turn will disrupt the boundary layer if one existed in the first place. Furthermore, except in cases where the flow velocity is nearly zero, the velocity of flow will make no difference in energy transfer. A Calorie of heat tranfers between two mediums at a constant rate depending on the material i.e. water, copper or aluminum. If you think about it 99.99% of any laminar flow occurs in the radiator.
 
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DorrellCO

Guest
Interesting thought on the whirpool deal. Here is a few shots of something similar I have been working on:

004.JPG

005.JPG

006.JPG


I got the best results with the goofy looking center inlet and duel outlet. In fact the results where very good. I am planing to make the circle more oval and make the center pins higher. Not quite a whirpool but the general idea.
 

BillA

choke man
Joined
Jan 2, 2001
a couple of (non mathematical) observations:
(Aesik is the math guy, I'm into testing)

nomenclature:
the commercial big shot of this idea was Chip of OCWC who peddled his "tidal pool" wbs far and wide, and claimed they were superior to the MCW462
they were not

I, and I think Gabe also, refer to the 462 "action" as 'die area impingment', because thats what's happening
(and technical papers in 'the literature' refer to it that way as well)
and just about everyone has now jumped on that bandwagon, even if they also have fins, or channels, or bumps, ets

because it is a superior performing configuration

SNIPER1M
"Furthermore, except in cases where the flow velocity is nearly zero, the velocity of flow will make no difference in energy transfer."

well, you are literally correct, but the implicit conclusion (that some may inferr) is quite wrong
heat in = heat out, no biggie
ahh, but the resulting temps due to "the velocity of flow" are not going to be 'the same' at all
while higher flow has no effect on the heat balance, it sure WILL affect the components' equilibrium temps
the heat convection rate increases with increasing Re, (but at an ever decreasing rate)

"A Calorie of heat tranfers between two mediums at a constant rate depending on the material i.e. water, copper or aluminum."

wrong,
try looking at the delta T, among many influencing factors

be cool
 
OP
G

G33k

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Mar 1, 2002
Location
Bristol [UK]
DorrellCO said:
I got the best results with the goofy looking center inlet and duel outlet. In fact the results where very good. I am planing to make the circle more oval and make the center pins higher. Not quite a whirpool but the general idea.

You might also try offseting the outlets to positions similar to those on my own block. I believe that doing this would induce some swirling inside the block which should improve heat transfer a little.

One thing I really want to try is running my block backwards to see if having the cold water coming in over the Die area actualy DOES make a significant differece...
 
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DorrellCO

Guest
G33k said:


You might also try offseting the outlets to positions similar to those on my own block. I believe that doing this would induce some swirling inside the block which should improve heat transfer a little.

One thing I really want to try is running my block backwards to see if having the cold water coming in over the Die area actualy DOES make a significant differece...
I thought about it originally but I cannot have any inlets/outlets on the side of the block because it will not fit in the case with the power supply right above it. I could try it on my test bench but why test a block that will not fit into a case later. I try to design the blocks to fit into all cases/mobos because I may end up selling them one day. Another thought though is having a angled inlet on top that willo swirl the water around in a circle and outlet in the middle.
 

Aesik

Member
Joined
Jan 6, 2002
It seems to me that most people are missing the point of what turbulence is. Tubulent flow in its simplest definition is mixed flow. The particles do not follow straight, organized streamlines as in laminar flow but rather follow erratic and varying paths. Another key point to understand is that there is not just laminar and turbulent flow, but degrees of each and a transition period between. Accordingly, as turbulence increases, so does the convective heat transfer coefficent, which in turn leads to more effective cooling.

IMO none of the blocks presented in this thread are going to create any kind of whirlpool effect. They are all more along the lines of impingement cooling. The water enters the block perpendicular to the block base and CPU and exits out the side. Even the Tidal Pool block probably doesn't setup much of a whirlpool effect, but rather just has the water enter in, flow around the block about 180 degrees, then exit. Truth be told, having a whirlpool effect that keeps some of the liquid re-circulating over the top of the core is exactly the opposite of what is desired to get good cooling. The best practice in blocks will always be to have the liquid enter and exit the block as fast as possible.

Sniper, I think you better study up on heat transfer a bit more before making such bold statements ;)
 
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DorrellCO

Guest
Aesik said:
It seems to me that most people are missing the point of what turbulence is. Tubulent flow in its simplest definition is mixed flow. The particles do not follow straight, organized streamlines as in laminar flow but rather follow erratic and varying paths.
That is why I used a center inlet over the posts in the center of my block to cause a varied flow and to push the coldest water in that spot aswell. Seemed to work good. And no, my block was not ment to be a whirpool really and is nothing of the sorts in reality.

So yes, good post!!!