Steel foam ?

[Tom]

I heard a Congressman mention this stuff in a hearing about armor, anyone ever heard of it ?

Sounds pretty interesting to me.

 

[Changlinn]

Wasn't that the stuff they were going to put on tanks, basically it can absorb a few direct hits before becoming useless, just another layer of armour really. I can't remember specifics though, I think metallic glass will be the better of the two...

 

[Gibsons]

Steel foam has been talked about for decades, it was floated as a potential product of space-based industries. I guess some progress has been made recently, but it all comes down to how cheap they can make it.

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Wasn't that the stuff they were going to put on tanks, basically it can absorb a few direct hits before becoming useless, just another layer of armour really. I can't remember specifics though, I think metallic glass will be the better of the two...

from your description, could either be reactive or highly spaced armor.

Newest US counters to the RPG threat take spacing to new level, sorta. Text

Reactive armor wroks, but can be deadly to nearby friendlies. Text

 

[irwincur]

That is definitely cool sh*t.

 

[The Boston Dangler]

Companies are trying to make foamed aluminium work for water cooling cpu's. Sorry, I lost the linkage.

 

[CycloWizard]

Originally posted by: The Boston Dangler
Companies are trying to make foamed aluminium work for water cooling cpu's. Sorry, I lost the linkage.

I wouldn't think foam anything would work well in this application, since it essentially traps air, decreasing the net thermal conductivity of the substance. I would think that having a thin, solid aluminum plate would be much cheaper and more effective.

I have a friend working on developing carbon foam for the USAF. I haven't talked to him for a while so I'm not sure what kind of application they're after, but I would imagine it would involve light weight, structurally rigid materials.

 

[The Boston Dangler]

The foamed aluminium passes liquid through the block, resulting in a very efficient heat exchange. There's no air in the block. I'm still looking for the damn page.

Foamed carbon sounds uber-cool. I'm thinking mile high buildings.

edit: this isn't the site i was looking for, but it will do.

 

[Gibsons]

Originally posted by: The Boston Dangler
The foamed aluminium passes liquid through the block, resulting in a very efficient heat exchange. There's no air in the block. I'm still looking for the damn page.

Foamed carbon sounds uber-cool. I'm thinking mile high buildings.

edit: this isn't the site i was looking for, but it will do.

As I understand it, if there's no air in the block, it's not a foam. Are their other definitions?

 

[The Boston Dangler]

If a sponge is full of water, it's still a sponge, yes?

The page I linked to describes open- and closed-cell types. Open-cell allows fluids to move within the structure.

 

[CycloWizard]

Originally posted by: The Boston Dangler
If a sponge is full of water, it's still a sponge, yes?

The page I linked to describes open- and closed-cell types. Open-cell allows fluids to move within the structure.

Well, that makes a lot more sense. You'd be increasing the surface area for heat transfer. The pressure drop would be rather large, necessitating greater pumping power, but it should allow slightly lower temperatures for watercooling applications. Interesting...

 

[Gibsons]

Originally posted by: The Boston Dangler
If a sponge is full of water, it's still a sponge, yes?

The page I linked to describes open- and closed-cell types. Open-cell allows fluids to move within the structure.

hm, semantics I suppose. I think the technical definition of a foam specifies liquid/gas phases so we're already past that definition... I suppose my nit-pickiness might be satisfied by calling it a highly porous substance created by a foaming process. Open cells aren't bubbles though, and I'd think that would be a requirement. Otoh, if the open-celled metal is made using a foaming process (using bubbles), then what the heck else will you call it? I suppose as long as we progress, we'll always have to make up new words or change definitions.

1. A mass of bubbles of air or gas in a matrix of liquid film, especially an accumulation of fine, frothy bubbles formed in or on the surface of a liquid, as from agitation or fermentation.
2. A thick chemical froth, such as shaving cream or a substance used to fight fires.
2.
1. Frothy saliva produced especially as a result of physical exertion or a pathological condition.
2. The frothy sweat of a horse or other equine animal.
3. The sea.
4. Any of various light, porous, semirigid or spongy materials used for thermal insulation or shock absorption, as in packaging.

 

[CycloWizard]

Originally posted by: Gibsons
hm, semantics I suppose. I think the technical definition of a foam specifies liquid/gas phases so we're already past that definition... I suppose my nit-pickiness might be satisfied by calling it a highly porous substance created by a foaming process. Open cells aren't bubbles though, and I'd think that would be a requirement. Otoh, if the open-celled metal is made using a foaming process (using bubbles), then what the heck else will you call it? I suppose as long as we progress, we'll always have to make up new words or change definitions.

I think you're technically right. In the world of catalysis, we call this sort of thing a porous substrate rather than a foam. The primary difference is that a foam contains bubbles from processing, while the other contains very specific distributions of pores, which are typically longer and much narrower than are bubbles. The pores allow things (including heat) to diffuse in and out of the substrate, whereas the bubbles do not, since they are enclosed within the substrate material.

 

[Howard]

http://www.cymat.com

 

[kleinwl]

I'm currently working on Alumium foam for next generation heat exchangers for automobiles. The foam, with very small "pockets" act as extremely dense fins. This significantly increases the heat transfer area (although Dp across the foam is fairly high).

While we do not know if this is going to be practicle, it has allot of potential and government funding.

 

[CycloWizard]

Originally posted by: kleinwl
I'm currently working on Alumium foam for next generation heat exchangers for automobiles. The foam, with very small "pockets" act as extremely dense fins. This significantly increases the heat transfer area (although Dp across the foam is fairly high).

While we do not know if this is going to be practicle, it has allot of potential and government funding.

Right, but the idea is that the fluid can flow all the way through the foam, correct?

 

[kleinwl]

correct...

The water (or air in the case of automotive / waterside cooling fins are normal copper an increase on the waterside fin density does not have much effective on the overall cooler efficency and just leads to plugging issues) runs through the foam using all the "pockets" (similar to any porus material) to flow through the material. While the fan load is high to achieve the necessary Dp across the material, the overall effectiveness is much higher, allowing for a small "footprint" and weight.

The one thing that I would watch out for in a water cooling solution using foam is plugging. Be sure to use de-ionized water (kept clean) to prevent plugging which will require replacement of the foam (since there isn't a good way of cleaning (Though perhaps acid etch would work... I haven't tried it).

Both Microchannel and Foam have the issue with plugging. We will have to see how that works out... but for air inside a case... there shouldn't be a problem.

 

[CycloWizard]

Right, that's what I figured. We were just busy getting caught up in the terminology, as most of us wouldn't really call this a 'foam' so to speak.

 

[da loser]

sounds similar to this stuff

aluminum and carbon foam

 

[kleinwl]

It is really important the the void size is small and consistant, otherwise your effective heat transfer is poor. There are a number of manufactures for aluminium foam... but only one or two in the world that have sufficent controls for "heat transfer" foam.

I expect that alumium foam will soon replace the cpu heat exchangers we see today. I've got a few samples on my desk that I'm planning on trying out with my current P4... but haven't had the time to do so.

 

[MrDudeMan]

Originally posted by: kleinwl
It is really important the the void size is small and consistant, otherwise your effective heat transfer is poor. There are a number of manufactures for aluminium foam... but only one or two in the world that have sufficent controls for "heat transfer" foam.

I expect that alumium foam will soon replace the cpu heat exchangers we see today. I've got a few samples on my desk that I'm planning on trying out with my current P4... but haven't had the time to do so.

awesome...you sound like you enjoy your job :thumbsup:

 

[Chode Messiah]

Currently there is testing for liquid armor between 2 plates of tungsten/depleted uranium. When hit, electric current turns the middle layer to liquid and then it resolidifies good as new