I Does combusted gas travel faster in a vacuum tube?

[Limebat]

TL;DR

Does combusted gas travel faster in a vacuum tube?

Hey all,
So if a gas is combusted, would it travel faster through a vacuum tube or a regular ole' tube? I would assume the vacuum tube, as there are less particulates collisions in the way of the fast-moving gas molecules. Yet this also implies pressure on the outside of the thin barrier _ 2, indicating a large pressure resistance would be met when puncturing the last stretch of the tube. I am unsure because I haven't taken any gas dynamics / thermo classes yet. It would help a good bit if anyone can answer!

- Bonus question:
If an object is put at the beginning of the vacuum tube, then the gas is combusted, would the projectile travel faster? I would assume the same idea would happen - less molecules in the way / other reasons not to. However, the combusted gas is assumed to fill only the area behind the projectile, not in front. Meaning vacuum dynamics would probably only apply to the projectile and its forces propelling it. So this probably turns into a classical physics problem, where:

Is an accelerating projectile faster in vacuum rather than not in a vacuum?

 

[jbriggs444]

Summary:: Does combusted gas travel faster in a vacuum tube?

Hey all,
So if a gas is combusted, would it travel faster through a vacuum tube or a regular ole' tube? I would assume the vacuum tube, as there are less particulates collisions in the way of the fast-moving gas molecules. Yet this also implies pressure on the outside of the thin barrier _ 2, indicating a large pressure resistance would be met when puncturing the last stretch of the tube. I am unsure because I haven't taken any gas dynamics / thermo classes yet. It would help a good bit if anyone can answer!

- Bonus question:
If an object is put at the beginning of the vacuum tube, then the gas is combusted, would the projectile travel faster? I would assume the same idea would happen - less molecules in the way / other reasons not to. However, the combusted gas is assumed to fill only the area behind the projectile, not in front. Meaning vacuum dynamics would probably only apply to the projectile and its forces propelling it. So this probably turns into a classical physics problem, where:

Is an accelerating projectile faster in vacuum rather than not in a vacuum?

So we have two identical guns. One has a thin piece of plastic over the end so that the barrel is evacuated. The other has the same thin piece of plastic over the end, but with a pinhole leak so that the barrel is filled with air.

We place identical shells in each gun's firing chamber. The shells have no bullet. Just propellant.

You want to know what, exactly?

Which piece of plastic breaks first if both guns are fired simultaneously?

 

[Limebat]

So we have two identical guns. One has a thin piece of plastic over the end so that the barrel is evacuated. The other has the same thin piece of plastic over the end, but with a pinhole leak so that the barrel is filled with air.

We place identical shells in each gun's firing chamber. The shells have no bullet. Just propellant.

You want to know what, exactly?

Which piece of plastic breaks first if both guns are fired simultaneously?

Ah, I would assume the one with the plastic end (no hole) would break first; until the combusted gas molecules hit the plastic walls, air resistance becomes the key player in the flame front velocities. Assuming the caps are infinitesimally small, meaning any applied chamber force could break either, the plastic end (no hole) would break first.

*Note; this is just a guess of mine. I'm not entirely sure if this is correct.