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Author: Subject: Aerosol BLEVE Bomb
tetrachloromethane
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[*] posted on 27-6-2005 at 12:18
Aerosol BLEVE Bomb


BLEVE (Boiling Liquid Expanding Vapor Explosion) refers to the explosion that occurs when a vessel containing liquified (by compression) gas is punctured.

Hmm... I wonder what would happen if an aerosol can was punctured?

I believe aerosol cans are made of steel, so a very strong acid or base could be added to corrode it. Also, a thermite mixture of FeO and Al could be used to melt the can.

Think of the explosion if a small can of liquid propane was punctured and a fire is nearby....:D

Any other ideas for this cheap, extremely destructive bomb?
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Lambda
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[*] posted on 27-6-2005 at 12:27
BLEVE


Tetrachloromethane, you should read about the Mexican city disaster, then you can see what a BLEVE can do. Sadely so, but many fire fighters perriched during this BLEVE, and they allso have it on film. I have not seen it yet, but it must be out there somewhere.

The military use this principle in FAX (fuel air explosives) bombs. They have about 3 - 5 times more destructive force than the same weight of commercial explosives. There are allso many patents related to the subject of FAX.

[Edited on 27-6-2005 by Lambda]
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tetrachloromethane
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[*] posted on 27-6-2005 at 13:08


I've heard of fuel-air explosives before. Although I never made one, I can imagine how powerful they can be. You mention how destructive these devices are, but isn't the purpose of this thread to discuss the production of massive instantaneous releases of energy?
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Lambda
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[*] posted on 27-6-2005 at 13:44
A given amount of energy releast over a long time versus short time


When you puncture an aerosol can and ignite the gas mixture immediatly, then you get a fairly slow process. This is because unreacted gas reacts with oxygen on the outer skirts of this burning fireball, and ureacted gas is still contained whithin. This gas contained within still has to mix with oxygen, and therefore all the energy is released over a fairly long time. The trick however, is to react a given amount of gas with oxygen in the shortest possible time, only then will a shockwave be generated with the most force. So now we come back to FAX, where this principle is applied. This intemitly mixed gas and oxygen (air) is ignited only after the mix has completed, and not before. This intemitly mixed gasmixture will then show a new phenomenon, namely detonation. In a detonation wave, you have so to speak an extremely fast moving reaction zone, which causes a lot of heat, and thus expansion of gasses in a very short time.
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tetrachloromethane
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[*] posted on 27-6-2005 at 14:01


Since the explosion would have such a large radius, the surface area of the fireball would be enough for an impressive display.

Enough with this theoretical bullshit, it would take hours to calculate if this would work.

Someone out there test this out and report back!!!:cool:
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[*] posted on 27-6-2005 at 14:57


Quote:

Someone out there test this out and report back!!!


Test it yourself. We're not your contract workers.

Furthermore, BLEVE is nothing new in the field of energetic materials. Unless you come up with something rather new, onorthodox or mindboggling, the lifespan of this thread is going to be rather short.




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[*] posted on 27-6-2005 at 16:29


From what I recall BLEVE are actually rather interesting. Superheated liquid is an energetic material and it seems like it is able to undergo a detonation-like phenomenon. Perhaps one could set off an explosion in a precise manner with a "detonator" charge (it being understood that it is the rarefaction, rather than the compression wave being amplified)?
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[*] posted on 27-6-2005 at 17:18


I remember reading a long time ago, about the effects of catastrophic failure of a supertanker carrying liquid natural gas. The liquid would immediately vaporise, absorbing heat from the surrounding water, and that would make a massive explosion by itself, just from the flashboiling. Then a single spark could ignite the gas/air mix, that (if this occured in a city harbor) would be hanging over the city. There was talk of it equalling a small nuclear explosion.

In my stupid days, a friend and I were out fuckin around with fire, and we did things such as putting aerosol cans in the fire... We were (probably luckily) too impatient to wait for it to burst -- it was leaking, and we didn't want to lose too much before it blew. So, we shot at it with a pellet gun, and thought we had punctured it... So seeing no show, we went up to it, I sat down under a meter from it, and put a pellet into the concave-hemisphere base of the can. It shot flame to, and past, me, and took off - we were lucky to not set the woods around on fire.

With fuel-air explosions the difficulty, I think is timing the ignition, which you would either have to determine experimentally or by calculation. I think that calculating it would be hard, but it may be easier than I think.




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[*] posted on 27-6-2005 at 18:16


On the subject of superheated liquids exploding, I have an interesting story. Years ago, I was playing with some capillary tubing. I took a piece, sealed one end, and added about 2 cm of water. Next, I sealed the other end a few millimeters above the top of the water level (not the best of seals, but it worked.) I put this onto a gas stove burner (on the metal, not touching the flame) and turned it on. At first, the water slowly expanded and eventually filled the entire tube. It then continued getting hotter, until it exploded, pulverizing the glass and leaving my ears ringing for a while. Luckily, I was about 5 feet away and behind something when this happened.

This really made me appreciate the power of a BLEVE explosion, especially given the fact that there was about a drop of water in there.:o
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[*] posted on 27-6-2005 at 21:17


With that appreciation in mind, consider how much mess a what, 200 gallon+ steel boiler would make at 500PSI?

Now add the momentum of a fully loaded locomotive behind the boilers...

...People had WAY too much fun in the 19th century. :D (Unfortunately during this experiment, a number of spectators were also killed :( )

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[*] posted on 30-6-2005 at 13:46


Quote:

So seeing no show, we went up to it, I sat down under a meter from it, and put a pellet into the concave-hemisphere base of the can. It shot flame to, and past, me, and took off - we were lucky to not set the woods around on fire.


So could a small rocket be produced utilising this phenomena as propultion?
idea:
An aerosol can with a nose cone on an attatched tripod above a fire with a small charge to open the bottom end?
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[*] posted on 30-6-2005 at 16:09


Sure -- you could make a rocket out of it.

Have you ever seen those little CO2 cars? Where I went to school, kids made them in Industrial Arts class (we called it Tech class, which the smarter schools reserved for computers and such). They are rocket-propelled wooden cars, driven by a 12g CO2 canister. They ran along a wire, and were launched by a device that punctured the canisters of a pair of cars at once. Then, at the other end, a little optical sensor system determined the winner of the race...

...Anyway, the point of all that is, anything that releases pressurized gas, it going to be capable of acting as a "rocket". But there is no point in using a flammable fuel in such a simple rocket - all the thrust is a result of internal pressure not combustion. The combustion takes place after it is no longer acting on the rocket body in any significant way.
Dry ice or LN would be a good choice, I expect, as they are relatively available, and don't pose any unnecessary hazards.


Edit -- therefore, the only benefit from setting it above a fire, is to increase the internal pressure. I don't know how much that helps.

[Edited on 1-7-2005 by Oxydro]




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[*] posted on 18-9-2006 at 00:54
American FAE BLU-96/B




The munition falls in the foreground well in front of the house.
What you don't see is the viewpoint from the left in which
another camera captures the blast effect on the inside.
If you remember those films of nuclear tests done at the Nevada
site to see the effects on homes and the occupants, this looks
practically the same. In the old days live animals would have
been used. Afterwards one would venture afield to inspect the
damage and come upon some poor pig wandering about dragging
its entrails, having been burst open by the overpressure.

http://www.hrw.org/press/2000/02/chech0215b.htm

.
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