Tiny Bubbles Key to Cooling Crazy Hot CPUs

Smaz writes "With future CPUs expected to generate as much as four times the heat of today's processors, wicking away that heat remains one of the biggest engineering hurdles in the biz. Researchers at Purdue have developed a pumpless liquid-cooling system that removes nearly six times more heat than existing systems. The trick, it seems, is in the tiny bubbles. From the Science Blog."

Comments

Cavitation?

[Ungrounded Lightning]

It will be interesting to see if the shock waves from the cavitation (the sudden formation of the tiny bubbles) affects the operation of the chip or erodes the surface, limiting the life.

Re:Cavitation?

[iggymanz]

The sound waves from hard disks and power supply fans surely already make more vibration on the CPU than this would

Re:Cavitation?

[br0ck]

Cavitation has nothing to do with vibration. The sudden changes in pressure in the liquid deform or destroy the material. I've seen better links, but try this article for more information about the complexities in measuring and predicting cavitation caused by bubbles.

Re:Cavitation?

[Guignol]

What your parent talks about is cavitation, the vibration you talk about is also a problem, but it has nothing to do with cavitation.
What your parent reffered to was the formation of very tiny bubbles that quickly collapse and release microjets which are very damaging to surrounding surfaces.
Those tiny bubles also have the (generaly) unwanted property of always orienting themselves so as to send the microjet against the surface of contact, thus making the problem more severe and less unlikely to happen that it might sound in a first thought.
Those nasty microjets can do a lot of damage and are the reason why stainless steel helices of boats still get corroded.
In the case of the proposed cooling system, the surface of the channels might be attacked by the released microjets until perforation, since it is so thin.

Clarification

[PseudoThink]

The researchers found that the system was 5.7 times better at removing heat than existing miniature pumpless liquid-cooling systems.

It's misleading to generalize "existing miniature pumpless liquid-cooling systems" to "existing systems", as was done in the discussion header. At least, it made me think article was about a cooling solution six times better than *ALL* existing cooling systems. Of course, this leads one to question how good "existing miniature pumpless liquid-cooling systems" are...

so in the future...

[Anonymous Coward]

you will hard boil an egg rather then fry it on your P12 256bit quad CPU.

darn, all have to get a new recipe book.

Cue the Don Ho Jokes...

[Pirogoeth]

Tiny Bubbles
Running WINE
Make me happy
Make my PC feel fine.

Tiny Bubbles
Make me warm no longer
With a feeling that I'm going to cool you
Till the end of time

So here's to the Boilermakers
And here's to Purdue
But mostly here's to a cooler CPU

Tiny Bubbles
Running WINE
Make me happy
Make my PC feel fine.

Guinness as cooling agent ?

[bushboy]

They mention bubbles in this article - well, it's common knowledge that bubbles in Guinness defy gravity !

So maybe these chips will be served with a Guinness cooling agent ?

A 500 year old cooling method can't be wrong !

I love my chips with Guinness !

Hic, arrrr

This brings me to my favorite rant...

[mykepredko]

Where does the heat go?

This seems like a nice technology to remove the heat from the CPU, but what I'm always wondering about is, where will the heat actually be dissipated into the environment? At some point, there has to be a heat exchanger where all this heat collected in the tiny bubbles is passed outside the unit. This is going to take a fair amount of space - one of these days we're going to see ads for heat exchangers that take up less space than the "standard" box available from Intel.

I'm looking forward to a Beowolf cluster not only performing amazing calculations but also heating the building it's in.

myke

Laminar Flow layer

[Skreamer]

It's the same principle used in cooling nuclear reactors - deals with the Laminar Flow layer in fluids. Pretty simple actually. The surface area of the bubbles (must be small or they begin to restrict the flow) is much larger than the surface area of the overall fluid. Sounds weird, but it's true.

Re:Pumpless circulation

[PerlGuru]

The benefit of "tiny bubbles" is the bubbles or transfering latent heat of vaporization into the channel (the energy required to boil the fluid), these bubbles also cause mixing of the fluid in the channel.

Two terms to look up if your interested in this aspect of Heat Transfer and Fluid Flow would be subnucleate boiling and the departure from it. There is a balance between the amount of boiling and the amount of heat transfer. Not enough and you don't get many benifits... too much and the large bubbles that form on the channel walls effectively create a steam void that has a much higher specific heat then the fluid used for cooling... basically it is acting as an insulator preventing heat transfer into the fluid in the channel... a very bad thing [tm]. That is where departure from nucleate boiling comes in (this being the good thing) departure being where it starts getting bad very quickly.

Think pot of water for spaghetti before the water really starts boiling... Oh, and I apologize for my horendous spelling but you don't have to spell to run a nuclear reactor.

Picture

[m0i]

For those who don't bother to read the article, here's a picture of the thing.