I think it's in Lee's thread.
http://forums.procooling.com/vbb/sho...&threadid=6032


JD, yeah, that's it, 1/16 tubes.

From the "CPU backside cooler" thread:

is this the one you wanted ben

http://www.rmc.ca/academic/mech/biog...images/jet.jpg


gulp. this is from ben i had 1.4mmID tubes with 2.5mm cups at the time.

this is the link for hydrolic calculations

http://www.lmnoeng.com/PipeDuct.htm

ok, i need a little bit more clarification on this 'sucking out' issue.

is the ratio i need to work out the outlet area:inlet area, or hydraulic diameter outlet:hydraulic diameter inlet?

if it is the latter, how do i calculate the hydraulic diameter of the outlet?

i have 3.5mm cups, with 3/32 tubes (2.38mm od, 1.67mm id)

Wouwe great block leejsmith. Can you compare the performancewith a WW in your system?

I had to dig pretty deep, to get some answers to some questions, including that one.

As has been pointed out, the hydraulic diameter can be calculated using the formulae for an annular duct, as found here:
http://www.lmnoeng.com/PipeDuct.htm

What it boils down to, is that the hydraulic diameter of the annular duct is equal to the gap between the outside of the jet tube, and the cup wall.

So... if that gap is smaller than the jet tube's ID, then the flow speed is higher as the coolant exits the cup, and that's the "sucking" effect that I'm talking about, which would significantly reduce the jet effect.


As for the distance of the jet's outlet, from the cup's bottom, I believe that there was a reference made to where it needs to be somewhere between 3 to 5 times the jet's ID. I could be off though.
[edit] I found it.
Also, some references here:
http://forums.procooling.com/vbb/sho...=&postid=81386

[/edit]

JD: I found a pic of the baseplate to the "Cascade", and I'm reposting it here, because I needed to show you something:

http://www.employees.org/~slf/c2/c22.jpg

There's a fine balance in the gap, between the cups. If it's too small, then there's not enough heat rravelling up the fin (aka gap). If the gap is too large, then the mass is too large, and accumulates heat. Cathar describes it, in his thread:
http://forums.procooling.com/vbb/sho...&threadid=6666

at the moment i can only compare againts a maze 3 but i do have a cascade on order.

Have you finished with the M3 yet lee?, or do you have some more designs/testing in the pipeline?...

I though the wall thickness was for structural strenght and the secondary impingment was 'incidental'?...

Far from it.

The second inpingement is what allows the baseplate to have any kind of structure, with the remaining copper there. The "incidental" really, is that if you use a 3/8" plate to start off with, you are left with a good structure that should remain integral, under the clamping pressure.

These remaining bits of copper act as fins, and the second inpingement allows it to function optimally, with minimal thermal resistance.

as i have a block that is 2C better than the maze 3 after many tests i can use that to compare againts so i will send it back asap.

thanks MDM.

btw i have some 3mm copper if you would like some.

They really are symbiotically linked. Quite a few things at play on that one.

You want the structural strength, true, and the cup walls give you that, so they are a necessary evil. The cups walls are also there to contain the off-flow from the jets to stop the jets from interfering with each other, so again they are necessary. The off-flow from the primary jet can be used as a "secondary" impingement. This secondary impingement is deliberate and not incidental because the cup width can be such that the impingement's efficiency is reduced. Since we have to have the walls there, we may as well make use of them in the conduction element of the cooling of the block to allow heat somewhere to go in extremely low flow scenarios otherwise the design will suck at low flow when the impingement effects start to lose their power.

hmmm...just a thought here, but has anyone thought of what might happen if one used square/retangular pockets instead of round holes?

How do you make a square hole that small?

Assuming that your holes are 1/8" in diameter it really should not be that bad. You can use one of your 1mm endmills...this would leave a .020" radius in the corners & a .085" flat....like so...

http://home.comcast.net/~jmcook3/square.jpg

Interesting idea. I have no clue if it would be better or not. If I ever get around to building this I might try it.

the whole square pocket/hole idea is based on something Cathar said...
now what I am thinking here is that by having many round holes in a pattern, the wall thickness between the holes are far from being a constant...that is it changes depending on what angle you are looking at. By having a pattern of squares, it is much easier to minimize the wall thickness of the cups....to more of a constant.

Disadvantage is is that it makes it more complex to make, but not overly so....especially for a non-production block.

How so?

What impact do you think that the current 0.25mm variation from the thinnest to thickest sections of copper walls between cups will have on performance?

Do you think that a non-circular chamber will significantly alter the secondary impingement in a negative fashion at the corners of the square, resulting in reduced efficiency where it's most needed (at the thicker wall sections)?

If you wanted to make the wall thickness more uniform, you'd concentrate on a hexagon shaped cup, not a square or a circle, however, one now has to consider what the impact will be on jet impingement efficiency now that the cup is no longer the same shape as the jet.

But that's incedental not designed for right? 0.25 is the thinest you could safely go I'd imagine(Cu IS soft! :D ). I thought about using brass and having 0.1 walls, 1 or 1.5mm cups to make the 'secondary' heatpath negligent?. Drilling straight through the brass and using copper 'foil' (0.2mm) for the bottom (you can buy it in varying thin gauges from RC/hobby shops I believe). But I don't know how 'fine' you could go without it cutting through the Cu when clamped?...

PS. I'd use surgical steel syringes for the jets. Not that I could ever make this (to 0.1mm accuracy) but it's good to dream :) ...
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Lee, Id love some 3mm copper. Cutting that 10mm stuff across the middle is a bitch!!

Well I changed course again . I know Bigben might start to :rolleyes:.:D

I have been tweaking the laser at work to try and get it back to engraving like new and have come as close as I can get being the boss doesn't want to spend a dime on getting replacement parts it desperatly needs...

Anyway I made a new desing today. It has 11 jets. The holes will be drilled with a 1/8" endmill into 1/4" thick copper. I will have to measure the jets once I get home with my micrometer as they are smaller than what they were drawn to be because the laser melts away a little more material than the design is drawn to. The holes I did a pilot hole with the laser and am going to attempt to drill them out with a drill bit.

Also this is a single inlet and SINGLE outlet design. I threw this together because I am trying to route 3 computers onto one loop and having 3 barbs on one block makes it a bitch. I will leave the Lemon Block though as the last block in the loop because it is the best block and because I can easily rought the dual outlets into the resivore.

My capture card is messed up again so it looks like I will have to reload the drivers and what not before I can put up anymore pics. Hopefully this weekend I can find sometime.

My prerogative. ;)

My prerogative. ;)

I needed a single inlet single outlet design for my multiple computer water cooling project so I had to change plans. And I decided to give the laser another shot. This time the jets came out pretty nice except the holes. I am hoping I can drill them out with out breaking them. Money is an object right now so ordering brass tubes or anything else is not a possibility. Not for a few months anyway. I attached the Corel Drawing of the new design in progress.