Ultimate block? Theory. - Page 11

bigben2k · 10-02-2002, 08:57 AM

I think that's unnecessarily tall. What flow rate are you targeting?

Cathar · 10-02-2002, 08:59 AM

Quote:

Originally posted by cristoff
so would that work well?

That would work better than most blocks on the market, depending on a few modifications and getting the base-plate thickness correct. I would suggest 1.5-2mm.

Cut the fins to be no more than 4mm high. Reduce the number of fins to just 20mm wide at best (unless you want to cool a peltier - in which case make them as wide as your peltier).

That'd get you a block that'd be better than most but still misses out on impingement action that would take it a bit further.

Micro-channels = good
Impingement = good
Micro-channels + impingement = better (best??)

cristoff · 10-02-2002, 02:07 PM

so it would work well with it shorter... better than most though, how?

whats impingement?

MeltMan · 10-02-2002, 07:46 PM

OMG this thread is still going? I saw this like months ago it seems like.

bigben2k · 10-02-2002, 08:28 PM

Quote:

Originally posted by cristoff
so it would work well with it shorter... better than most though, how?

whats impingement?

Inpingement is putting a restriction in the flow, strictly for speeding up the coolant, over a very short range. Think about a nozzle.

It's effective because it increases the flow speed over a critical area: the inside of the block where the CPU core is.

Cathar · 10-03-2002, 12:06 AM

Quote:

Originally posted by bigben2k
Inpingement is putting a restriction in the flow, strictly for speeding up the coolant, over a very short range. Think about a nozzle.

It's effective because it increases the flow speed over a critical area: the inside of the block where the CPU core is.

Not quite the defintion of impingement.

Impingement in the dictionary sense means "to collide".

Water flowing down some channels don't "collide" with the surfaces, just flow along.

Impingement in water-cooling terms means making the water "collide" with a surface. The best surface for that is the surface that sits directly above the CPU core. The effectiveness of impingement cooling is directly linked to the velocity of the water striking the surface. By carefully restriction openings at various locations (ie. nozzles) we can greatly accelerate the water velocity to more rapidly strike the surface, and as a result improve the convectional co-efficient of the metal-water layer and cool more efficiently.

[Edit - I said velocity then said flow after - when really I was meant to be referring to velocity at all times]

godsdice · 10-03-2002, 01:07 AM

This is correct, however it's not due to an increase in water flow, just velocity...they are different. What's special about impingement is that it creates a thermal boundary layer (like a thin layer of highly turbulent decelerating water) governed by convection. Convection is more efficient at small-scale heat transfer in this thin layer than conduction with a normal, laminar flow.

Furthermore, and I'm not entirely familiar with flow dynamics, a higher Reynold's number (velocity, pressure, density) translates to higher heat transfer with conduction or convection... right?

joeyd · 10-05-2002, 01:21 AM

well i'm no expert of anything but why haven't we seen hybrids like in the heatsink world. a heat sink of both aluminum and copper. now i know your going to say the battery affect but why not use a slug of copper about twice the size of the core on the bottom of the water block but have aluminum right after it so that the copper never touches the water . Or how about even silver and alumminum. would this not increase performance and lower costs ? I would build one myself but i don't have the tools and of course i can't build anything.. i tried making a box outta plexi glass for my rad , pump , res and well its i dunno what it is .... hehe ...

godsdice · 10-05-2002, 01:36 AM

Wait, what's the point of having the copper slug transfer to the aluminum and then to the water? Why not just make the whole thing aluminum?

There are several blocks that are copper and aluminum in order to save money. But really the all-copper ones aren't that much more expensive and generally perform better.

Now, I don't see how incorporating silver would reduce cost... some people have made blocks out of silver coins and I remember there was a plexiglass silver block on the market a while ago but they don't at all perform in accordance with their price.

Cathar · 10-05-2002, 01:37 AM

Quote:

Originally posted by joeyd
well i'm no expert of anything but why haven't we seen hybrids like in the heatsink world. a heat sink of both aluminum and copper. now i know your going to say the battery affect but why not use a slug of copper about twice the size of the core on the bottom of the water block but have aluminum right after it so that the copper never touches the water . Or how about even silver and alumminum. would this not increase performance and lower costs ? I would build one myself but i don't have the tools and of course i can't build anything.. i tried making a box outta plexi glass for my rad , pump , res and well its i dunno what it is .... hehe ...

How would using aluminium and not copper help when touching the water?

joeyd · 10-05-2002, 01:42 AM

sorry if i didn't make myself clear enough . I would have a thin layer of aluminum right before the water to prevent the battery effect. if for no other reason(think of the highend alphas, alluminum but with the copper heatspreader plate forged in). I have been told that copper absorbs heat quicker than aluminum but aluminum dumps heat quicker. I'm not sure if thats right. I just started studying must of this stuff in college. And i'm just asking much smarter people . (that would be you guys) Also a silver / aluminum heatsink would most likely cost the same as an all copper one but what if it performs better ?

Cathar · 10-05-2002, 01:46 AM

Quote:

Originally posted by joeyd
I have been told that copper absorbs heat quicker than aluminum but aluminum dumps heat quicker.

False.

They both "dump" heat at the same rate, whether it be water or air.

This is a common myth that started a while back with the Swiftech MC462A heatsinks.

joeyd · 10-05-2002, 01:48 AM

see someone much smarter corrected me already :-) now whats the diffrence between the two and silver ?

godsdice · 10-05-2002, 01:49 AM

Quote:

Originally posted by joeyd
I have been told that copper absorbs heat quicker than aluminum but aluminum dumps heat quicker.

http://www.procooling.com/articles/h..._-_phaes.shtml

godsdice · 10-05-2002, 01:55 AM

Quote:

Originally posted by joeyd
see someone much smarter corrected me already :-) now whats the diffrence between the two and silver ?

Silver has a higher thermal conductivity than copper or aluminum. Looking in my notes here it is 245 vs 227 copper and 128 aluminum (alloy 1100). This is in units BTU/(h)(ft)(degF)

joeyd · 10-05-2002, 01:55 AM

Thanks for the link it was a great read....

Cathar · 10-05-2002, 01:59 AM

Quote:

Originally posted by joeyd
now whats the diffrence between the two and silver ?

All solids "give up" heat at the same rate, no matter what they are.

The convection of heat from a solid surface to a liquid or gas is totally dependent on what's going on with that liquid/gas at the solid's surface. The only part the solid has in the equation is how much surface area it can present to the liquid/gas.

What does change between solids is how fast they can conduct heat from somewhere hot to where the heat can be dissipated.

Silver is about 5% better at conducting heat than copper, and copper is about 90% better than aluminium at conducting heat. Silver is the best metal for conducting heat, but due to its cost, copper which is only very slightly behind makes much more sense.

joeyd · 10-05-2002, 02:03 AM

well now that i just got a crash course in all this ... wouldn't a silver heatspreader be ideal in a waterblock? has this been done with any of the leading blocks of today ?

godsdice · 10-05-2002, 02:09 AM

Honestly I don't think anyone uses silver in the computer cooling industry besides AS thermal compounds and a brief silver block (which I think was from OCH so that doesn't really count). One reason, which I forgot to mention, was that silver has a very high densitiy. If you think copper is hard to machine just try silver...No I wouldn't even think of using silver anywhere. Money is better spent buying a better radiator or pump.

joeyd · 10-05-2002, 02:17 AM

yes i can see your point , but i'm just talking about a heat spreader.. it wouldn't have to be more than twice the size of the core which is really nothing forged into the coper at the base where the core and the block meet .

Cathar · 10-05-2002, 03:50 AM

The silver->copper interface will never be "perfect". As such, the hybrid metal block will always perform worse than an all copper block because the thermal junction between the silver and the copper will more than offset the 6% thermal conductivity gain that silver grants over copper.

joeyd · 10-05-2002, 03:26 PM

okay ,now i understand , thank you for explaining it to me

bigben2k · 10-05-2002, 06:29 PM

If it's any help...

We discussed the same issue right here

We came to the same conclusion, more or less.

What might be of interest is that silver cold plate, with a TEC, but I'm not sure it's worth the expense.

10-02-2002, 08:57 AM	#251
bigben2k Responsible for 2% of all the posts here. Join Date: May 2002 Location: Texas, U.S.A. Posts: 8,302	I think that's unnecessarily tall. What flow rate are you targeting? __________________ WBTA (Water Block Testing Alliance) Nordic Hardware WC 101

10-02-2002, 02:07 PM	#253
cristoff Cooling Savant Join Date: Mar 2002 Location: Mass Posts: 185	so it would work well with it shorter... better than most though, how? whats impingement? __________________ fr33t3chi3

10-02-2002, 07:46 PM	#254
MeltMan Cooling Savant Join Date: Aug 2001 Location: KS Posts: 374	OMG this thread is still going? I saw this like months ago it seems like. __________________ MeltMan Lurker Supreme!

10-05-2002, 01:21 AM	#258
joeyd Cooling Savant Join Date: Apr 2001 Location: new jersey Posts: 142	well i'm no expert of anything but why haven't we seen hybrids like in the heatsink world. a heat sink of both aluminum and copper. now i know your going to say the battery affect but why not use a slug of copper about twice the size of the core on the bottom of the water block but have aluminum right after it so that the copper never touches the water . Or how about even silver and alumminum. would this not increase performance and lower costs ? I would build one myself but i don't have the tools and of course i can't build anything.. i tried making a box outta plexi glass for my rad , pump , res and well its i dunno what it is .... hehe ... __________________ soyo dragon kt333. axp 2000 1gig of ddr333 ati radeon 9700 pro My Heatware

10-05-2002, 01:42 AM	#261
joeyd Cooling Savant Join Date: Apr 2001 Location: new jersey Posts: 142	sorry if i didn't make myself clear enough . I would have a thin layer of aluminum right before the water to prevent the battery effect. if for no other reason(think of the highend alphas, alluminum but with the copper heatspreader plate forged in). I have been told that copper absorbs heat quicker than aluminum but aluminum dumps heat quicker. I'm not sure if thats right. I just started studying must of this stuff in college. And i'm just asking much smarter people . (that would be you guys) Also a silver / aluminum heatsink would most likely cost the same as an all copper one but what if it performs better ? __________________ soyo dragon kt333. axp 2000 1gig of ddr333 ati radeon 9700 pro My Heatware

10-03-2002, 01:07 AM	#257
godsdice Cooling Neophyte Join Date: Jan 2002 Posts: 29	This is correct, however it's not due to an increase in water flow, just velocity...they are different. What's special about impingement is that it creates a thermal boundary layer (like a thin layer of highly turbulent decelerating water) governed by convection. Convection is more efficient at small-scale heat transfer in this thin layer than conduction with a normal, laminar flow. Furthermore, and I'm not entirely familiar with flow dynamics, a higher Reynold's number (velocity, pressure, density) translates to higher heat transfer with conduction or convection... right?

10-05-2002, 01:36 AM	#259
godsdice Cooling Neophyte Join Date: Jan 2002 Posts: 29	Wait, what's the point of having the copper slug transfer to the aluminum and then to the water? Why not just make the whole thing aluminum? There are several blocks that are copper and aluminum in order to save money. But really the all-copper ones aren't that much more expensive and generally perform better. Now, I don't see how incorporating silver would reduce cost... some people have made blocks out of silver coins and I remember there was a plexiglass silver block on the market a while ago but they don't at all perform in accordance with their price.

10-05-2002, 01:48 AM	#263
joeyd Cooling Savant Join Date: Apr 2001 Location: new jersey Posts: 142	see someone much smarter corrected me already :-) now whats the diffrence between the two and silver ? __________________ soyo dragon kt333. axp 2000 1gig of ddr333 ati radeon 9700 pro My Heatware

10-05-2002, 01:55 AM	#266
joeyd Cooling Savant Join Date: Apr 2001 Location: new jersey Posts: 142	Thanks for the link it was a great read.... __________________ soyo dragon kt333. axp 2000 1gig of ddr333 ati radeon 9700 pro My Heatware

10-05-2002, 02:03 AM	#268
joeyd Cooling Savant Join Date: Apr 2001 Location: new jersey Posts: 142	well now that i just got a crash course in all this ... wouldn't a silver heatspreader be ideal in a waterblock? has this been done with any of the leading blocks of today ? __________________ soyo dragon kt333. axp 2000 1gig of ddr333 ati radeon 9700 pro My Heatware

10-05-2002, 02:09 AM	#269
godsdice Cooling Neophyte Join Date: Jan 2002 Posts: 29	Honestly I don't think anyone uses silver in the computer cooling industry besides AS thermal compounds and a brief silver block (which I think was from OCH so that doesn't really count). One reason, which I forgot to mention, was that silver has a very high densitiy. If you think copper is hard to machine just try silver...No I wouldn't even think of using silver anywhere. Money is better spent buying a better radiator or pump.

10-05-2002, 02:17 AM	#270
joeyd Cooling Savant Join Date: Apr 2001 Location: new jersey Posts: 142	yes i can see your point , but i'm just talking about a heat spreader.. it wouldn't have to be more than twice the size of the core which is really nothing forged into the coper at the base where the core and the block meet . __________________ soyo dragon kt333. axp 2000 1gig of ddr333 ati radeon 9700 pro My Heatware

10-05-2002, 03:50 AM	#271
Cathar Thermophile Join Date: Sep 2002 Location: Melbourne, Australia Posts: 2,538	The silver->copper interface will never be "perfect". As such, the hybrid metal block will always perform worse than an all copper block because the thermal junction between the silver and the copper will more than offset the 6% thermal conductivity gain that silver grants over copper.

10-05-2002, 03:26 PM	#272
joeyd Cooling Savant Join Date: Apr 2001 Location: new jersey Posts: 142	okay ,now i understand , thank you for explaining it to me __________________ soyo dragon kt333. axp 2000 1gig of ddr333 ati radeon 9700 pro My Heatware

10-05-2002, 06:29 PM	#273
bigben2k Responsible for 2% of all the posts here. Join Date: May 2002 Location: Texas, U.S.A. Posts: 8,302	If it's any help... We discussed the same issue right here We came to the same conclusion, more or less. What might be of interest is that silver cold plate, with a TEC, but I'm not sure it's worth the expense. __________________ WBTA (Water Block Testing Alliance) Nordic Hardware WC 101

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