Powdered Chemical Rocketry

[Spacescifi]

Since powder is more dense than fluid, yet can easily be turned to fluid, would it be possible to create  a kind of propellant powder that could be converted easily to fluid again for a rocket engine?

 

I am thinking more dense fuel storage but with the same advantages of chemical rocketry.

 

Methane powder is a thing, and I reckon it is binded with something... probably salts.

 

Would be cool if some lighter gases could be powderized or at least made into a thicker more dense fluid (like hydrogen, helium,  oxygen, etc).

 

Oh... this is cool:

https://www.purdue.edu/uns/x/2009b/091007SonRocket.html

 

https://www.nature.com/articles/news.2008.1077

Edited August 20, 2021 by Spacescifi

[cubinator]

Solid propellants are often compressed powders.

[steuben]

The problem with powder-fluids is mixing. To keep things from getting very ... interesting when used in rockets (how interesting you may ask. "Oh god, oh god, we're all gonna die" levels of interesting) the mixing has to be _very_ uniform.  If it isn't, you'll get hot spots, then burn throughs, then... interesting times. Hmm... maybe I should reread "Ignition!" always a fun book.

I haven't read through the Perdue article... but a quick buzz on it, it looks like they have a different fuel for the solid fuel panty. It's a neat idea though.

[Meecrob]

51 minutes ago, Spacescifi said:

Since powder is more dense than fluid

Is it though? Yes the solid matter of the powder is more dense than the liquid version, but the whole reason we classify it as a powder and not a solid is because there is a lot of air in between all the grains of powder.

[DDE]

1 hour ago, Spacescifi said:

Would be cool if some lighter gases could be powderized or at least made into a thicker more dense fluid (like hydrogen, helium,  oxygen, etc).

A substrate that doesn't burn is going to obliterate any boons of high density that you're going to obtain. There was plenty of research on poweders and slurries, including aluminium, beryllium and carbon. All reported similar findings: difficulties with handling and storage, limited gain. Aluminum only burnt fully when used with fluorine.

[Meecrob]

Ah, flourine...the chemical everyone LOVES to handle!

[kerbiloid]

The metastable metallic hydrogen powder.

[Spacescifi]

1 hour ago, DDE said:

A substrate that doesn't burn is going to obliterate any boons of high density that you're going to obtain. There was plenty of research on poweders and slurries, including aluminium, beryllium and carbon. All reported similar findings: difficulties with handling and storage, limited gain. Aluminum only burnt fully when used with fluorine.

Purdue article is using water ice with alluminum somehow?

 

No mention of fluorine that I saw...

 

Even said they want to make a gel of the stuff.

 

Funny eh?

 

Future propellant be like hair gel LOL.

[DDE]

22 minutes ago, Spacescifi said:

Purdue article is using water ice with alluminum somehow?

Not sure they suceeded where the 1970s guys failed. Aluminium "cleverly" coats itself with aluminum oxide, and stops further combustion. I'm guessing they're using essentially nanothermite to get past that.

Also, I've only ever heard of ALICE as a lOx-Al slurry.

[JoeSchmuckatelli]

I'll ask here - because it seems on topic... 

Does a hot burning solid like Thermite produce more gas expansion than something cooler like powdered aluminum? 

(And would Thermite be a good SRB material?) 

Edited August 20, 2021 by JoeSchmuckatelli

[magnemoe]

2 hours ago, steuben said:

The problem with powder-fluids is mixing. To keep things from getting very ... interesting when used in rockets (how interesting you may ask. "Oh god, oh god, we're all gonna die" levels of interesting) the mixing has to be _very_ uniform.  If it isn't, you'll get hot spots, then burn throughs, then... interesting times. Hmm... maybe I should reread "Ignition!" always a fun book.

I haven't read through the Perdue article... but a quick buzz on it, it looks like they have a different fuel for the solid fuel panty. It's a neat idea though.

This, now as I understand modern fuel air bombs tend to use powder, but this is probably more to do with all the various conditions you might use it. From winter in Afghanistan to an rain-forest during monsoon. 

[DDE]

1 minute ago, magnemoe said:

This, now as I understand modern fuel air bombs tend to use powder, but this is probably more to do with all the various conditions you might use it. From winter in Afghanistan to an rain-forest during monsoon. 

AFAIK it's the opposite. Older bombs tried using effectively coal dust. ODAB-500 uses 1,3-pentadiene.

[kerbiloid]

7 hours ago, JoeSchmuckatelli said:

Does a hot burning solid like Thermite produce more gas expansion than something cooler like powdered aluminum? 

(And would Thermite be a good SRB material?) 

Fe₂O₃ + 2 Al → 2 Fe + Al₂O₃

It doesn't produce any gas. It's full solid.

[AHHans]

14 hours ago, Meecrob said:

Ah, flourine...the chemical everyone LOVES to handle!

I think you mean: "Flourine, the chemical that LOVES everyone!"

In order to pretend to be on-topic: for high I_sp you not just want lots of energy in your reaction, but you also want lightweight reaction products (that move faster than heavier molecules at the same energy).  Most solids will react to molecules that are significant heavier than H₂O, so that is an additional drawback of the idea.

 

[kerbiloid]

1 hour ago, AHHans said:

16 hours ago, Meecrob said:

Ah, flourine...the chemical everyone LOVES to handle!

I think you mean: "Flourine, the chemical that LOVES everyone!"

"Fluorine: the love gas."

[DDE]

2 hours ago, AHHans said:

I think you mean: "Flourine, the chemical that LOVES everyone!"

Fluorine. The yandere gas.

[SOXBLOX]

MOAB is filled with a compound that's 21% powdered aluminium by weight...

[kerbiloid]

And 79% not.

[SOXBLOX]

2 hours ago, kerbiloid said:

And 79% not.

True.

[JoeSchmuckatelli]

On 8/21/2021 at 1:02 AM, kerbiloid said:

Fe₂O₃ + 2 Al → 2 Fe + Al₂O₃

It doesn't produce any gas. It's full solid.

Confused.  How does Thermite burn without producing gas?  Something has to be liberated as gas to combust, doesn't it? 

[kerbiloid]

3 minutes ago, JoeSchmuckatelli said:

Confused.  How does Thermite burn without producing gas?  Something has to be liberated as gas to combust, doesn't it? 

Not necessary. It just redistributes the oxygen from less active metal to more active one.

It makes gas out of what's around.

P.S.
Well, technically it temporarily gets liquid.

P.P.S.
Its burning temperature is nearly equal to the boiling point of both iron and alumina, so it sprays around

[magnemoe]

2 hours ago, kerbiloid said:

Not necessary. It just redistributes the oxygen from less active metal to more active one.

It makes gas out of what's around.

P.S.
Well, technically it temporarily gets liquid.

P.P.S.
Its burning temperature is nearly equal to the boiling point of both iron and alumina, so it sprays around

Yes and that is the nice thing about thermite it does not produce a lot of hot gas then burning like gunpowder, if you don't want that thermite is nice. 
Think an variation of it is used to weld stuff like railway tracks. 

[kerbiloid]

33 minutes ago, magnemoe said:

Think an variation of it is used to weld stuff like railway tracks. 

In Firefly Saffron used it (probably) to weld the pilot cabin door.

Edited August 22, 2021 by kerbiloid

[DDE]

3 hours ago, kerbiloid said:

In Firefly Saffron used it (probably) to weld the pilot cabin door.

There's also the mundane topic of government-sanctioned arson.

[kerbiloid]

And look: all they need is iron oxide and aluminium, it doesn't need air, and that's exactly what they are going to have on the Moon.

Looks like the main weapon of the lunar infantry will be the thermite balls and a sling.

The 345th Inf. Bat. "The Moonslingers".

The 354th RoboCavalry Sq. "The Ball Riders" on Boston Dynamics donkeys.

Edited August 23, 2021 by kerbiloid