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Author: Subject: Detonation Velocity of organic explosive cannot exceed 11 Km/s
MineMan
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[*] posted on 3-5-2016 at 16:05


Donier,

I am wondering though if that equation should have some boundary conditions though? If I put and EBW through the length of the explosive than the VOD would be near the speed of light (assuming the wire explodes at the rate that current travels through it?)

What am I missing here?
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careysub
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[*] posted on 3-5-2016 at 16:35


Quote: Originally posted by MineMan  
Donier,

I am wondering though if that equation should have some boundary conditions though? If I put and EBW through the length of the explosive than the VOD would be near the speed of light (assuming the wire explodes at the rate that current travels through it?)

What am I missing here?


Could you show your work? This is a somewhat puzzling statement.

Exploding wires are not detonations. They are explosions that develop over time as energy is fed into them, the peak current flow and heating occurring during the early stage of wire plasma expansion.
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MineMan
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[*] posted on 3-5-2016 at 16:43


I don't have any work to back this up. It is just a thought experiment...

The wire turning into plasma will detonate the explosive simultaneously though, thus making the VOD (in one axis) the same speed of this reaction from the wire. I am presuming....
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[*] posted on 3-5-2016 at 18:08


Bridge wires aren't very long, for practical purposes it is initiation at a point like with other detonators, with the detonation expanding outward as usual.

You can do much better with a slapper detonator (or on an even larger scale an explosive driven flying plate) which will initiate an entire surface simultaneously. This is not "infinite detonation velocity" though - just a whole bunch of initiation points over an entire surface (the limiting case) and the detonation proceeds at normal velocity in a direction normal to the initiation surface.

This is how air lenses are used to arrange for perfect spherical implosions.
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MineMan
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[*] posted on 3-5-2016 at 18:53


Right bridgewires are not usually that long, and are meant to initiate at a point...but it is certainly possible to make them run through the whole axis of the explosive, which would initiate more surface area than a slapper disk or the such. If that was done, what would the VOD in the longitudinal axis be....

Detcord running through the length of an emulsion cartridge greatly increases the VOD of the emulsion... I would expect and EBW to do the same if it were long enough. I don't know if it would have any practical applications, but it would be interesting to see the results...
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Microtek
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[*] posted on 3-5-2016 at 22:06


In a traditionally initiated HE, the shock wave gathers strength as it travels through the mass of explosive, much like an avalanche or a laser does. Initiating the mass throughout its length, negates this effect, so I would not be surprised if this would actually diminish the brisance of the explosive in tests such as the plate dent test.
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[*] posted on 4-5-2016 at 01:19


Quote:
Initiating the mass throughout its length, negates this effect, so I would not be surprised if this would actually diminish the brisance of the explosive in tests such as the plate dent test.

Mineman is correct, Microtek ─ initiation at multiple points, or at all points along an axis would certainly increase brisance of emulsions and the higher VOD of detcord would be expected to contribute to that increase.




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PHILOU Zrealone
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[*] posted on 4-5-2016 at 11:02


Quote: Originally posted by a nitrogen rich explosive  
Can you U2U me some of them for me to evaluate?

You evaluate my molecules?
When you have already hard time evaluating your own brew ones...:(




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clearly_not_atara
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[*] posted on 4-5-2016 at 13:00


I think you've excluded from consideration the sulfur-nitrogen derivatives while forgetting that this class of compounds is relatively unexplored (due to toxicity, instability, and difficulty of synthesis). Tetranitro tetrasulfur tetraimide, S4N4(NO2)4 might be particularly explosive, if it can be synthesized at all (draw it by following S8 > S7NH > S6N2H2 >> S4N4H4 and replacing H with NO2).
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PHILOU Zrealone
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[*] posted on 5-5-2016 at 04:42


Quote: Originally posted by clearly_not_atara  
I think you've excluded from consideration the sulfur-nitrogen derivatives while forgetting that this class of compounds is relatively unexplored (due to toxicity, instability, and difficulty of synthesis). Tetranitro tetrasulfur tetraimide, S4N4(NO2)4 might be particularly explosive, if it can be synthesized at all (draw it by following S8 > S7NH > S6N2H2 >> S4N4H4 and replacing H with NO2).

While interesting idea...theorically, practically it will not be very interesting...

Why? Because replacing all C atoms by S atoms in energetic molecules means that:
-you will eventually increase the density a little what is favourable for detonic parameters
-you will change the high energy providing CO2(g) (8.19 kJ/g) for nearly half that with SO2(g) (4.64 kJ/g)

But S4N4 is a sensitive negative OB with medium power on its own and eventually by making a binary out of it by admixing a positive OB HE...this might lead to something interesting

--> S4N4 / HONH3NO3
--> S4N4 / N2H5NO3
--> S4N4 / NH4C(NO2)3
--> S4N4 / N2H5C(NO2)3
--> S4N4 / HONH3ClO4
--> S4N4 / N2H5ClO4
--> S4N4 / N2H6(ClO4)2
--> S4N4 / C(NO2)4
--> S4N4 / C2(NO2)6

But this should be less interesting than binaries with superfuels based on CxNy like:
-dicyanoacethylene
-hexacyanobenzene
-tricyano-s-triazine (cyanuric tricyanide)
-hexaazidobenzene
-triazido-tricyano-benzene
-cyanuric triazide
-dicyanotetrazole
-dicyanotetrazine




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clearly_not_atara
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[*] posted on 8-2-2024 at 09:14


It appears that this assertion may have been defeated in an unexpected manner. The novel superhard material tl24-CN2 is reported to have a gravimetric energy density (Hf) greater than RDX:

https://onlinelibrary.wiley.com/doi/full/10.1002/adma.202308...

Since the speed of sound in diamond is 12 km/s, it's likely similar in these superhard nitrides, so if they can be coaxed into detonating, the VoD would necessarily be even higher.

This is an end-run around the OP argument: instead of packing more energy into the molecule, the bulk modulus was instead pushed to an incredible value.

EDIT: The paper also mentions the high-pressure synthesis of the current (inorganic) champion, lithium pentazolate, VoD = 11.3 km/s (calculated).

[Edited on 8-2-2024 by clearly_not_atara]




[Edited on 04-20-1969 by clearly_not_atara]
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