Any news on the cascade xxx?

[BillA]

jlrii
keep digging, better things out there
and the pricing will cool your ardor

[myv65]

Late to the game, but wanted to toss out some comments about those Cathar made regarding 304/316 stainless. We use these materials frequently for items with variable water contact, ranging from stagnant to turbulent and varying between submerged or not. Generally speaking, in my experience rust is only a problem if the steel has been contaminated, generally by manufacturing processes that handle both stainless and plain carbon steels. A good passivation process normally takes care of such contamination.

That said some of the water we deal with does have bad actors that will attack the 18-8 family of stainless. In many of these cases this is addressed through either going to a duplex stainless ala 2205 or a specific paint procedure.

I would not expect the fluid contents and temperatures of a typical water cooling system to cause any trouble for 304/316.

I'm just wondering what experience or data has led to your conclusion regarding the rusting of 304 and 316.

[jlrii]

Originally Posted by unregistered

jlrii
keep digging, better things out there
and the pricing will cool your ardor

Yeah from what I've seen CVD=$$$. Their PDF brochure says,"Costs: Competitive with existing high-end thermal
materials; less than 1/10 the cost of traditional CVD
diamond materials"

The stuff I've seen b4 is around $1800 for a single slug so if their advert is true that puts it around $2-300 per 50mm slug (Minimum "sample" order of 10 pcs BTW). Nice to think about but too much money for DIY. I imagine you could use a fairly small piece tho', using impingement there isn't really any need to cover much more area than the die takes up.

[Cathar]

Originally Posted by unregistered

Cathar
you are aware of EK's testing, some of which yielded a higher OC with a higher CPU temp ?

you realize that with a resistor network you can model your bp ?
then you can back-calculate to get a fit for the different bps
but then you will need to address the thermal lag (capacitance) which affects the OC
gets too hairy for me when it is then necessary to characterize the magnitude and duration of the thermal transients

EK? Am aware of my own testing though where I found the same thing, and promptly drew the ire of a certain forum admin leading to my banning from LiquidNinja's for daring to suggest such.

Basic summary of my prior testing which led me to this point:

Test 1) Cascade => Overclock stability quite dependent on flow-rate despite relatively small changes (<2C) in overall CPU temperature. By altering the water temperature I was able to ascertain that the overclock stability issue had a far wider effect than the overall CPU temperature. i.e. The high-flow scenarios would remain stable at 5C higher indicated CPU temperatures than the low-flow scenarios. Hypothesis: Uneven cooling effect across each cell resulting in hotter locations for the lower flow rates affecting overclock

Test 2) Thicker bp Cascade (essentially a copper Cascade SS without jet mods) => Overall CPU temperatures slightly higher and overclock stability was about the same at higher flow rates. Better overclock stability and better temperatures at lower flow rates than regular Cascade. Hypothesis: thicker bp provides a better "smoothing" effect

Test 3) Cascade SS => thicker bp than regular Cascade, jet modifications. Markedly improved overclocks in all scenarios (low/high flow rates), including holding higher overclocks at higher CPU temperatures. Improved overall temperatures. Undoubtedly some of the benefit seen was due to the silver used facilitating greater lateral thermal spread. Some gain also due to jet mods.

Basically all that is telling me that despite the original Cascade giving pretty good temperatures across the board, the actual temperatures weren't really telling the full story. Mind you, the original Cascade was giving me the best overclocks of all the blocks I tested it against, so I guess that's why I rested on it for a while.

Bill, I'm sure that a test setup can be made to measure all this. Electronics aren't my strong point though as I'm a relative noob in that area. Sure, I can find my way around a multimeter, but proper part selection and setup and control is something I'd need assistance with.

[Cathar]

Originally Posted by myv65

Late to the game, but wanted to toss out some comments about those Cathar made regarding 304/316 stainless. We use these materials frequently for items with variable water contact, ranging from stagnant to turbulent and varying between submerged or not. Generally speaking, in my experience rust is only a problem if the steel has been contaminated, generally by manufacturing processes that handle both stainless and plain carbon steels. A good passivation process normally takes care of such contamination.

That said some of the water we deal with does have bad actors that will attack the 18-8 family of stainless. In many of these cases this is addressed through either going to a duplex stainless ala 2205 or a specific paint procedure.

I would not expect the fluid contents and temperatures of a typical water cooling system to cause any trouble for 304/316.

I'm just wondering what experience or data has led to your conclusion regarding the rusting of 304 and 316.

Hi Dave,

My experience with 316 is rather limited, but based upon the Laing D4 pumps I ordered in. Even after sitting overnight and damp after a test, I opened one pump the following morning to discover rust spots had formed.

Now I guess I should point out that where this happened was where the metal had been "marked" by various inspection chops (red stamped writing), and it may very well be that this was enough of a "contamination" to result in the rusting I saw.

In any event that immediately scared me off 316. My other concern arose from the galvanic differences between stainless and copper/silver. When in an passive setup, which I understand to mean running water where there is no fixed ionisation loop occurring, galvanic corrosion isn't really an issue, but for an active setup where the two metals are in constant ionised contact with each other then the PD appears to be enough to sustain a slow reaction. Not as dramatic as aluminium/copper, but enough that over time the 316 will get eaten away.

Now I'm no expert on this, and this is what I've managed to deduce from Googling around, so I will happily defer to someone with more experience who can definitively answer yes/no to either of those two points.

[BillA]

banned ? you mean like JoeK did to me here ? lol, their loss
EK are the initials of OPPainter of xtremesystems.org, bit of an OCer

did not mean to suggest a hardware 'solution' using resistors, I was talking about software simulation as thermal and electrical resistances are calculated the same way
examples here, all nodes are connected via resistors

[Cathar]

Originally Posted by unregistered

banned ? you mean like JoeK did to me here ? lol, their loss
EK are the initials of OPPainter of xtremesystems.org, bit of an OCer

did not mean to suggest a hardware 'solution' using resistors, I was talking about software simulation as thermal and electrical resistances are calculated the same way
examples here, all nodes are connected via resistors

Actually I think I got banned right after I told a certain admin what I thought of their practise of reading and using the content of Private Messages between forum members in public posts. Some comment about me being antagonistic towards the site for what the site says is common practise as far as they are concerned. I don't know what came over me - getting upset about something that is a federal offense here in Australia.

The issue is not so much with breaking down the simulation like you describe, indeed that's pretty much what I've done. The issue is confidence that I've done it right. At some stage practical results are going to yield better data than theory, and I'm pretty much at that point.

[Les]

Originally Posted by Cathar

....
The issue is not so much with breaking down the simulation like you describe, indeed that's pretty much what I've done.......
.

Does your simulation predict better cooling directly under a "cup"?
My crude models using heatspreading and convection coefficients give little enlightenment.
Think that a detailed analysis(including convection profile) by programs like TAS may be necessary to answer even that simple question.

[BillA]

I have TAS and it won't do this as it has no CFD solver
one has to enter a value for h, the convection coefficient
this guts the calc as h is the great unknown (for me at least)

[Les]

Originally Posted by unregistered

I have TAS and it won't do this as it has no CFD solver
one has to enter a value for h, the convection coefficient
this guts the calc as h is the great unknown (for me at least)

h is also the great unkown to me.
I would probably try a Flomerics calculated h for an average value within a cup. Rather unsatisfactory and not a profile but ...................

[Cathar]

Originally Posted by Les

Does your simulation predict better cooling directly under a "cup"?
My crude models using heatspreading and convection coefficients give little enlightenment.
Think that a detailed analysis(including convection profile) by programs like TAS may be necessary to answer even that simple question.

Like Bill says, it's a bit of a mystery even to me. I can plug values in for h based upon observations, and reckon I might have an idea, but h is not something that I'm mathematically determining. Basically it's a process of "do some theory", build a block, measure it, revise the theory, make changes, and repeat.

I'm fairly confident that for lower flow rates (<4LPM) that the areas immediately under the jets where stagnation occurs are the hottest sections. At higher flow rates I believe that behavior slowly changes, but that perhaps the ratio of jet diameter to bp thickness is still perhaps a little too low. I also believe that there's also a small issue with the triangle cross-over between 3 adjacent cups at lower flow-rates, which is another thing that's changed on the XXX.

I think the main issue here is that h is varying very widely depending on both the flow-rate, and the actual location within any one cell, which of course is fairly obvious given jet theory, but I guess what I think I didn't anticipate is the magnitude of the effect that it is having on CPU overclock stability, which has caused me to re-think my strategy on ultra-thin (<1mm) bp's.

[Cathar]

Some piccies of the first-cut XXX prototype next to a regular Cascade. Note, neither block has been cleaned up after machining so they look a little messy.

[Les]

Originally Posted by Cathar

... I can plug values in for h based upon observations, and reckon I might have an idea, .......

It impossible to get a value of " h based upon observations" with no true DeltaT or W and an assumed C/W(TIM).

[Cathar]

Originally Posted by Les

It impossible to get a value of " h based upon observations" with no true DeltaT or W and an assumed C/W(TIM).

You can determine where h is roughly at on an average. Is it exact? No. I didn't even begin to claim that it was. 'tis all theory and approximation until nailed down by someone with substantially more research funds and time than I have.

[BillA]

whew
gonna need a filter on that puppy
the Cascade I tested was filthy when I borrowed it, and I'll be damned if it was not somewhat dirty after I finished - and I have a 20 micron filter
-> high performance has high requirements

[Cathar]

Originally Posted by unregistered

whew
gonna need a filter on that puppy
the Cascade I tested was filthy when I borrowed it, and I'll be damned if it was not somewhat dirty after I finished - and I have a 20 micron filter
-> high performance has high requirements

I've actually found that the Johnson/Jabsco in-line strainers to be pretty effective. I fill my loop with water that's been fed through a 10 micron filter first anyway, and so long as the loop was clean initially the blocks remain fine.

Still though, yes, "micro-structure" blocks do place a very high requirement for a clean system.

[Les]

Originally Posted by Cathar

You can determine where h is roughly at on an average. Is it exact? No. I didn't even begin to claim that it was. 'tis all theory and approximation until nailed down by someone with substantially more research funds and time than I have.

Here suggested some "possible h"s for the WW.
However with Kryotherm only dealing with channels am unable to do the same with the Cascade.
Some rough numbers would be interesting.

[Cathar]

Originally Posted by Les

Some rough numbers would be interesting.

Rough average estimates only for h for Copper Cascade.

h =~ 80000 at 10LPM
h =~ 55000 at 5LPM
h =~ 30000 at 2LPM

[Les]

Ta
Seem in keeping with Flomerics based guesses.
Wonder what TAS would make of them.

[BillA]

what are you guys doing ?
a nominal device average is worthless
h is location specific and different also per the conditions
this is what the gridding and nodes are all about