Point taken, but this an average within a cup.
There being 50+ cups per device, it may be a starting point.
Only this guy's opinion.

perhaps, but this touches on my heartburn with CFD for wbs
sure, one can sim a cup, test, correct, and validate
but this does not address the cups' interconnection necessary for any device calc;
nor, more importantly, does it enable 'looking' at the effects of cup changes (of any sort I suspect)

yea, perhaps better than nothing - but for me not worth my time if not predictive
Flotherm is very capable for many things, but I have reservations about its abitity to model mbs w/o extensive parametric validation
if I have to pay $28K pa per seat for Flotherm, plus a pHD to run it; and then STILL have to test 'till hell freezes over to validate, . . . its cheaper to build and test

Cathar,

No material expert here, either. In going through my book I find that the electrode potential differential from copper to silver is ~0.5V, copper to chromium (stainless surface chromium dioxide) is ~1V, and copper to aluminum is ~2V. All this is at 25°C.

From what you described of that pump, I'm reasonably confident it was a matter of contamination. Nonetheless, if contamination is likely in a typical system then I'd agree stainless ought to be avoided, especially in extremely narrow passageways.

Would this affect my system much? Metals in contact with water = brass, copper, silver. Ive not noticed any corrosion yet but I dont want 0.5v coming from the waterblocks. Also note the silver is not touching any other metal in contact with water.
Maybe this would be god for a new thread, on corrosion testing? If someone could deisgn a test for corrosion, that could be done accuratly, I do have silver, brass, copper, steel, and alu I can test with.

Cathar your xxx block pics look like they will be great performers. Could I have a XXX-SS block once you start making them (Ill supply the silver, got plenty here :D)
Also how much more jets do you think will be possible to add into that small an area?
Any plans to make GPU versions?

Will you continue making blocks once youve desiged something better for non-reseach purposes (if you ever did?) or will the old designs either get discontinued or licenced to other companys for manufacture? (like D.Tec/WW).

|kbn|. In a standard water-loop copper/brass/silver are basically galvanically unreactive with each other. The silver->brass difference is pushing it somewhat, but it is basically safe for long periods (many months -> years). At least that's what I've been able to ascertain on-line, and having run a copper/silver/brass loop totally unprotected in terms of corrosion inhibitor for about 6 months now the silver has only just started to develop a mild discoloring, which is about the sort of reaction level I would have expected.

The XXX blocks I only intend to make in silver for the bases. Am giving very serious thought to putting copper tops on them though just for strength as I don't really want to risk another repeat of a bad polycarb batch resulting in cracking tops. This would also allow the block to be thinner, as in 16mm high instead of the current 20mm.

Am giving serious thought to calling such blocks "Cascade XS", and dropping the XXX code-name moniker.

Damn, now the "I'd hit that" joke when you post pics of the finished product isn't going to be nearly as funny.

When I took out my silver gpu block it had no noticable change in colour. I had been using it for a month or two.

Cathar as silver is a lot more expensive than copper, and that the acctual cooling area in your block is ~30mm2 at most? You could do what I intend to reduce the cost some what.
My dad has made the silver into 20mm squares 8mm thick and they are accuratly made. We intend of fitting the silver into accuratly made copper blocks so that we get the advantage of silver, but without the cost. If this could be accuratly done on the scale you intend without problems of the jets/ cups not lining up, I think it would be a good idea and make silver blocks more affordable. They just wont look as shiny - silver is very easy to get a very nice shine.
Silver will perform better but would depend a lot on the deisgn to take advantage of it, I look forward to any test results from this new block in both materials.
some people might still want 100% silver bases though.
Copper tops would be nice, (none of this annodised alu crap :eek: ), but plastic may be best for your design. I recommend non brittle plastics like polyethelene instead of accrylic, never used poly carb though.

XS is a nicer name than XXX-SS :)

It will be interesting to see how this new block compares to the original with half the jets blocked off, when used on an athlon xp. Any estimate on how the pressure drop will compare to the original?

Which code are you using and how small do you want your capillaries?
 

Which finite element code are you running? ANSYS? or NASTRAN? OR ? and have you considered using self assembled or lithographically etched tubes?

I am using a concoction of my own writing. I suppose it could be classified as a finite-element analysis tool, but it's horribly primitive by modern day professional standards and has no fancy visualisation tools. Best bit though is that it is free, apart from me spending some time to code it up.

Self-assembled?

Have discussed lithographically etched tubes with someone. Biggest issue appears to be that everything needs to be squarish.

All you need is a synchrotron.....
 

No - I mean self assembled nanotubes using a mask and PMMA like the big boys.

My issue seems to be that we're talking 10-50 nanometers for the tube using self assembly and more for a mask like that used for the wafer.

Maybe I can try something at this end.

-talc

Nanometers? We're still dealing with hundreds of microns here.

Big boys? Sorry, doing what I can on a budget that amounts to around $1500 US max.

Happy to know if there's some way to do things better though.

Cather, at the risk of stating the bleedin' obvious. The "smoothing" effect of a given volume of copper must be related to it's heat capacity. Coppers heat capacity is less than that of water but not by a huge amount when stated relative to volume (4.2ish vs 3.5ish J/cm^3.°K).
That said, water IS better, by 15-20% so the more water in the vicinity the better the dampening must be. i.e. the thinner the baseplate the better. The dirty big fly in the ointment is the TIM-BP-H2O thermal resistance, which might nullify any benefit, leading to, thicker BP must be better, above a certain thickness.What that thickness is I don't know, it might be near zero. A direct die cascade would be interesting. ie no cup bases, the base of the "cup" being the surface of the CPU die.
What I am say is that I am concerned that all the tests showing that direct die cooling gives higher temperatures may be missing the point. The, lets call it "Maximum Attainable Stable Frequency/°C", might in fact be higher, thanks to the high specific heat capacity of water, even though the actual cpu temp could be higher. What the WW and than Cascade showed for me was that mass of copper (or silver) is not important for maintaining good temperatures. What is important is the way the water is delivered to the hot area. Deliver it in the same way direct to die and I can not see how it could be worse.
I am not a direct die advocate, actually I've thought it inferior because of the necessarily smaller surface area, but with impingement in the equation and your observations of overclock stability, I am beginning to wonder.

Cheers

Incoherent

I happen to have page 5 of this thread from before the crash still open. I'll repost. I hope no one minds. Unfortunately, those spiffy diagrams of cup bases and discussions of such were on page 4. :cry:

Thank God someone managed to save page 5 at least! Sad we lost page four, but perhaps we can resume the thread from here.

Great job guntledweasel! ! :D

Man!, I can hardly wait to see the results of the next prototype comparisson of the two alturnatives for advancing the Cascade XS design.

Now I have to admit I'm sort of glad I missed on the last order of SS Cascades. Now I'll be able to afford a Casscade XS instead.

According to Cathar, he wont make them for sale.



Messy, some from OCAU. But the core is here.

Adams,Foster,and Round sometimes talk crap.
However we all think.

Well Cascade II is what I'm refering to TerraMax. These proto type blocks are plainly that. I'd rather get the silver version of the Cascade II or XS or whatever Cathar decides to call it.

And with optimisation of the cup bases as well as tube numbers and sizing, it should work very well.

Note that my interest in this Cascade XS only came about when talk shifted to the base alterations. While shrinking tht tubes and making them more numerous also means they will be even easier to have them clog. With fewer tubes than the XXX Cascade the Cascade with altered bases interests me far more. It's greater machinablity combined with higher performance should be nothing short of great.

And I'd no illusions TerraMax that these were ready for the market at this time, or even soon. But the base alterations IMO will be the key to finding the optimised design for the next version of the Casscade.

Les
it is easier to ignore the statements of the uninformed

Blackeagle
fanboyism is cool, but your enthusiasm exceeds your accuracy

the TC4
http://thermal-management-testing.com/wbCWcomp.gif
others
http://thermal-management-testing.com/summar3.gif

so the TC4, a good block in its day, was subsequently exceeded handily by the MCW5002, among others (AquaJoe, etc)
if you describe history, get it right
and your ability to forecast the future is questionable as you are outside the 'group' that is making it happen

there is a truly large amount of research/data on jet impingement (in a confined area), and the ability to model such is 'easy' (with $$$$$$ of course)
- Cathar's activities should be appreciated for what they are, the balls out search for the highest performance possible

sure there are a few who will pay big bucks for 'the best' (me too, eh ?)
but do not confuse such with mainstream WCing
- stay tuned, you will see the manifestation of just exactly this point in several weeks

Bill,

Bad day? :shrug:

Fanboyism? I'll gladly plead guilty where Cathar is concerned. The blocks he's brought to market have moved the boundrys back a good bit in water cooling. And if he comes up with a Cascade II or whatever name he might give it, it'll help to keep the other block makers at work to improve.

Love the little hints you like to drop. I'm always interested in new stuff coming out.

Have a nice day! ;)

there is much not apparent to 'outsiders' (who fail to lOOk)

for another example (if you did not follow my hint on jets) take the RBX,
ALL of its features are extensively described in 'the literature', whether the (non-DD) designer knew of them or not
(I have my suspicions regarding such, but no facts obviously)
-> do not be confused, the RBX is an advance based on the WW, even if not particularly well implemented (or presented to the public)

is Cathar an impetus to the commercial wb mfgrs ?
for sure, all this to his credit (I'm a fan of his as well, eh ?)

but remember always that there are many ways to skin a cat;
mfgrs make products that can be sold at a profit, such is our system
yes, Ford owns Ferrari; but this was not done to improve the Fiesta

I keep following developments and when I see actual figures I begin to wonder if diminishing returns point was passed some time ago? All the energy and time and $$$$ spent on Cascade SS and super small tube sizes.... is the improvement substantial enough to justyfi it? Don't get me wrong here, I don't want to be a party pooper but I like to ask such questions :)

On the side note, I think it was Les who posted link to a page with some calculator dor convective heat transfer coeeficient for a water jet. It remided me of another thread about Cathar's blocks here on procooling. I reminded me of this thread bacause drawing showed on this calculator page neatly supported my suggestion for improvemnt of jet type block - designing out stagnation zones while at the same time increasing surface area and jet pressure by decreasing&modelling cross sectional water jet area.
This would allow for bigger diameter jets, fewr ot them, cheaper (shorter) CNC and higher stress durability.

Earlier on Cathar was quoted writing about the need for suoer clean system... micro water filters.... I think BillA is right by saying this is not for the masses :)

At the risk of revealing myself to be the uninformed outsider that I am...
Bill, it sounds to me like Cathar is quite interested in making changes that may impede performance a bit, with the gain of simplifying the design and making the block significantly easier to machine. Perhaps "highest performance produceable" would be more accurate?

Sweet, I sure hope we can take this to mean Swiftech's gonna have a new block out soon?

ZOMG they're gonna hire Cathar! :eek:
Kidding, kidding....I wouldn't want to imply that Swiftech is in any way not a "performance" manufacturer.

edit:typo

Oh we're way passed profitability: we're nearing insanity here! ;)

You can find some articles here:
http://www.cooling-electronics.com/html/articles.html

gruntledweasel
define the measurement criteria
its not temps, its the OC that Cathar is using to define performance
(with which I concur even if NOT an OCer myself)

Ben
more productive will be those publications beginning with "Journal of . . . . .
go to the Uni, expect to spend some days
digest that, then start on the "Proceedings of . . . . .
lots more days

no free lunch

The Uni?!?

???
http://www.uni.edu/
???

OZ lingo, any University/Engineering library
-> access to these huge dbs of tech papers

My ignorance has been revealed and duly noted then, eh? Ah well, it was bound to happen in any case.
A pity we lost a page of discussion, as I think that's where my misunderstanding has come from...I thought there were two linked issues here, Cathar's concern over the need to cool micro-hotspots on the core (OC being the tool to measure success at such), and an epiphany he'd had regarding a way to ease his difficulties in manufacturing. Did I see a distintction where there was none? Or was I just unclear about which of Cathar's comments I was referring to?

Did I misinterpret the context of this statement?

edit: Ignore me, questions answered by the man himself below.

Believe me, the thought crosses my mind too. At some point (economical) rationality does leave the stage, but such is true of various motor sports as well. For example, one can buy a stock Yamaha R1 motorbike, stick a custom exhaust pipe and slicks on it for ~$15000US, and set lap times around a race track that come within 10% as fast as what would be achievable with a ~$500000 fully factory kitted SuperBike. Like Bill says about the Ford/Ferrari thing.

This is precisely something that I'm exploring. I will state something here though. The jet-in-a-cup principle has similar premises to the free-jet model, but overall the convectional area offered by the surface of the cup wall cannot be ignored.

Larger jets with more fully developed convectional activity at the base of the cup comes at the expense of larger cups. The further the walls move away from the jet (in a ratio sense) results in a increase of the ratio of "conduction distance to convectional surface area". i.e. the net convectional efficiency may get improved at the base of the cup, but we lose out double time on the walls as the water velocity there will be slower, and the heat has to move further up the walls to engage the same convectional area.

So again there's the balance. The principle of the Cascade somewhat sacrifices maximum convectional efficiency at the base of the cup, but attempts to make up for this by placing the jets at a distance that maximises the Nusselt number in the stagnation region immediately under the jet. This (smallish) loss then gets made up in the cup walls. The smaller the cups (and the smaller the jets as a result) the less distance the heat needs to travel up the cup walls. The smaller the cups in comparison to the jets (to a point) the greater the walled surface area that gets engaged for the same vertical distance from the CPU, and the greater the rate of convection due to increased water velocity (which decreases with radial distance from the jet).

That's the basics of the "constrained jet behavior" that I've been looking at. It does have some similarities to free-jet behavior, but overall I feel that they are actually quite different in terms of what configurations work best for either.

Still, this won't stop me from trying this second, more easy to machine prototype based upon more standard free-jet principles, but while using slightly larger jets, this actually leads to a significantly more restrictive block due to significantly less jets (which is not desirable except for those with well-above-average pumps), and indeed to shrink the free-jet design down to a point where the walls are effectively working in a similar fashion to the Cascade approach, the jets are now even smaller than they would have been on the Cascade, leading to an super-restrictive block.

gruntledweasel
Cathar(Foster) sometimes guesses wrongly.