Would FP "self contain" in Space? (ie. no air pressure)

[stix]

Or is the phenomenon dependent on ambient air pressure?

[Mike]

I would expect so, but also expect a higher critical mass. The reason for this is that even in space you still got inertia that alows you to build up the confinement.

[stix]

I'll take your word for it. Is someone able to test this?

[taiwanluthiers]

I wonder if anyone could try it in a vacuum chamber...

[gregh]

You also have to take gravity into account. The mass of the top of the pile is adding to the containment of the bottom.

[taiwanluthiers]

That complicates things... only thing you could do is a sealed vacuum chamber, and then drop the thing from a great height while igniting it (to simulate zero G)

[stix]

... only thing you could do is a sealed vacuum chamber, and then drop the thing from a great height while igniting it (to simulate zero G)

 

Now that's a project!

[ORMDale]

I would say absolutely yes, due to gravitational and inertial confinement. But if we're gonna take it to space as in zero gravity space, how would you keep it in a nice neat pile while you lit it?

[Ubehage]

I would say absolutely yes, due to gravitational and inertial confinement. But if we're gonna take it to space as in zero gravity space, how would you keep it in a nice neat pile while you lit it?

Interesting problem.

I think if you release it as a pile, very gently, it may stay together long enough for you to ignite it.

 

Then comes the question of self-confinement:

Down to basics, it's a matter of how fast it's burning vs the acceleration of the mass away from ignition-point.

Here on Earth, that acceleration is slowed a bit by both gravity and air-pressure/resistance. In space, you only have to account for the mass itself.

So I think you'll need a bigger mass, and then it will self-confine.

 

I think the answer lies in black holes:

They started out as a f*cking big star, whose core exploded. The expanding core collided with the outer layers, and the self-confinement was so extreme that the core collapsed back in on itself.

So yea, self-confinement is a thing, even in space.

[taiwanluthiers]

I think even black powder needs confinement in order to ignite properly at high altitudes... so it probably plays a role....

[Arthur]

Black powder certainly needs confinement and fails in a vacuum.

[Mumbles]

The other thing that might come into play is heat conduction. Air is a good, but far from perfect heat conductor. A total vacuum is a perfect insulator. You'd lose out on particle to particle heat conduction, which might impede it's flame conduction. I have no proof of it, but I'd expect flash or BP to burn slower in a vaccum from this, and all of the previously mentioned factors.

[Arthur]

BP is so pressure sensitive that parachute deployment charges in high power rockets have to be better compounded than simple BP.

[MadMat]

Mumbles, While you would loose heat convection in the vacuum of space, I believe you would still have radiation and (if the particles remained in physical contact) conduction (aluminum is a great conductor of heat) . All in all, yes I believe it would also burn slower.

Edited October 19, 2015 by MadMat

[taiwanluthiers]

I believe bp burn rate is fairly consistent regardless of pressure, however that's from atmospheric pressure and up. At lower pressure perhaps due to the lack of heat convection bp burns slower. So with rockets at higher altitudes the charge must be confined.

[CaverCork]

In regards to the original question of self confinement, I would say no. This is based on the assumption of a free mass in deep space where there are no nearby gravity wells, no solar wind or radiation, and a constant velocity. The only caveat would be the actual gravitational mass of each grain of powder which should only serve to keep the powder together, providing no other force comes into play. But, since space is not empty, could your little mass gravitationally attract more mass until it creates a sufficient gravity well of it's own and then self confine? Anything is possible, however improbable it may be. Edit: This also assumes the mass of FP is not great enough to form it's own gravity well. If the mass is great enough to do this, then the answer would be yes.

Edited October 30, 2015 by CaverCork

[Niladmirari]

In space (without air) heat is transferred by infrared radiation.

[MrB]

In space (without air) heat is transferred by infrared radiation.

Once you light the stuff, that has very little relevance. The expanding hot gases provides the only relevant atmosphere. So i'm pretty sure it would ignite the whole volume. I'd assume it would go "wosh" rather then "bang" and as such, in a no gravity environment, it wouldn't self-confine in "reasonable" volumes. Your going to need quantities that makes inertia let the damn thing go boom, and without gravity, and air-pressure, i think that would be quite a bit more then what goes bang on it's own in a more, down to earth, scenario.

B!