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A whole bunch of questions about electromagnetic acceleration for the experts

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Bruhathkayo

Mon Sept 17 2012, 02:20PM

Registered Member #6571 Joined: Mon Sept 10 2012, 10:57PM
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Posts: 3

Could a railgun be used to accelerate conductive fluids like mercury or a eutectic of lead and bismuth?

I did some reading on magnetic refrigeration,

My reasoning is that if it's possible to keep the working material as a liquid inside of the machine, it might have some desirable properties. Won't jam, and fills the entire volume of container holding the material, flow diameter could possibly be adjusted. But if it's possible for it to exit the railgun as a solid through some method (magnetic refrigeration or something else) then it would have all of the desirable properties of a solid moving through air. Is this possible? What might happen if you run an electric current through the ejected stream?

I read a little here,

and it seems that the viscosity increases if running an electric current through a conductive fluid. That may improve the properties the fluid has when traveling through air.

My other question is on plasma armatures and plasma stealth. Over here,

it says that a plasma sheath around an object would improve its aerodynamics. Is it possible to combine that with the idea of a plasma armature so that the entire projectile is "coated" in plasma?

My final question is could an induction coilgun be used to accelerate projectiles made of lead or tungsten?

Thanks in advance.

Ben Solon

Tue Sept 18 2012, 02:43PM

Registered Member #3900 Joined: Thu May 19 2011, 08:28PM
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Posts: 600

not my area of expertise, but i'll add.

why refrigerate the fluid when you could just use the fluid to push a ceramic projectile? if you found a fluid with desirable parameganetic properties, then the fluid would keep in shape due to the massive em field in its own line. plus if you has a mix of lubricant in it then the projectile would only give minimal wear on the rails.

i don't know anything about plasma physics so nothing to add there. and the last thing is the liquid properties again. if you find a perfect paramagnetic fluid then all you're problems are solved

Ash Small

Tue Sept 18 2012, 03:02PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

ben123324 wrote ...

if you find a perfect paramagnetic fluid then all you're problems are solved

would ferrofluid be of any use here?

Forty

Tue Sept 18 2012, 03:24PM

Registered Member #3888 Joined: Sun May 15 2011, 09:50PM
Location: Erie, PA
Posts: 649

I don't think ferrofluid would be any good. or any ferromagnetic material actually. I have thought about using mercury or some other liquid metal that easily coats stuff to coat the rails and act like a lubricant, rail errosion resistance, more uniform conduction path, and possibly as a plasma armature as it is vaporized. of course most hobbyists wouldn't want to be vaporizing mercury anywhere near them.

and about the cooling of the liquid projectile as it leaves, assuming that it's still even a liquid and not a plasma, I don't think you could pull enough heat out of it in such a short distance/time frame to make it solid again.

I don't know much about aerodynamics of plasma sheaths.

an induction gun can theoretically accelerate any conductive, no ferromagnetic material. although if you want to shoot something more dense (as it sounds) then something like a copper casing or moving sled would probably be better to launch those less conductive materials like lead and tungsten.

Bruhathkayo

Tue Sept 18 2012, 08:08PM

Registered Member #6571 Joined: Mon Sept 10 2012, 10:57PM
Location:
Posts: 3

ben123324 wrote ...

not my area of expertise, but i'll add.

why refrigerate the fluid when you could just use the fluid to push a ceramic projectile? if you found a fluid with desirable parameganetic properties, then the fluid would keep in shape due to the massive em field in its own line. plus if you has a mix of lubricant in it then the projectile would only give minimal wear on the rails.

i don't know anything about plasma physics so nothing to add there. and the last thing is the liquid properties again. if you find a perfect paramagnetic fluid then all you're problems are solved

That's a good point. I've thought about suspending lead pellets or something similar in the working fluid.

Would fluids work in a helical railgun?

Gomez

Wed May 08 2013, 10:18PM

Registered Member #2328 Joined: Tue Sept 01 2009, 03:44AM
Location: Denver, Colorado, USA, Sol-3
Posts: 7

It's called an MHD pump.

lauriethepigeon

Fri May 17 2013, 11:22AM

Registered Member #7669 Joined: Mon Oct 29 2012, 02:55PM
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Posts: 19

LIMs are widely used in industry to 'pump' molten metals, so it's doable, like others have said it would depend on the magnetic properties of the metal

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