Steam Explosion and TNT equivalance
Steam Explosion and TNT equivalance
(OP)
Good Afternoon,
I am looking for any references that I can use to support that the pressure developed in a steam explosion (water on a molten metal pool) does not create the overpressure which develops when a true explosive is detonated.
A am trying to develop pressure mitigation hardware for a VAR furnace. and the engineer before me has (very conservatively, IMO) used SFPE Ideal Overpressure versus scaled distance curves, converting the energy of the steam expansion to TNTequivalent mass to determine the effects on the room structure, and then to define dificult parameters for which to design safing hardware.
Basically are there a references that state that steam explosions are not detonations, so that I can remove the conservatism from the analysis and redesign the safing hardware
Thanks!
I am looking for any references that I can use to support that the pressure developed in a steam explosion (water on a molten metal pool) does not create the overpressure which develops when a true explosive is detonated.
A am trying to develop pressure mitigation hardware for a VAR furnace. and the engineer before me has (very conservatively, IMO) used SFPE Ideal Overpressure versus scaled distance curves, converting the energy of the steam expansion to TNTequivalent mass to determine the effects on the room structure, and then to define dificult parameters for which to design safing hardware.
Basically are there a references that state that steam explosions are not detonations, so that I can remove the conservatism from the analysis and redesign the safing hardware
Thanks!





RE: Steam Explosion and TNT equivalance
Without going into numbers and quantities, I do not think there can be an answer to your question (which itself is not very clear to me).
Ciao.
RE: Steam Explosion and TNT equivalance
There are some pressure pulse figures resulting from various molten metal/water explosions in this paper:
http
It may be a starting point for further investigations.
Trevor Clarke. (R & D) Scientific Instruments.Somerset. UK
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RE: Steam Explosion and TNT equivalance
I would agree with you that equating the energy of steam to equivalent energy of TNT will overstate the blast pressure and blast damage potential of the steam.
Predicting peak pressure of TNT blast is a bit problematic, but you can start with:
"The velocity of detonation is approximately 22,300 fps.
(from ref. http:/
Detonation velocity is driven by the speed of sound of the reaction products behind the detonation wave, so the temperature of the reaction is thus known, if you know the reactant gas species.
It may be simpler to just compare the blast wave speed - an explosion can accelerate debris no faster than the speed of sound behind the shock wave, which for a steam explosion, you can predict from knowledge of the steam pressure and temperature. Compare the two speeds, the TNT will be an order of magnitude or so higher....
Or you can use your pressure argument (two ways of saying the same thing). This paper gives both detonation velocities and pressures for a variety of high explosives:
www.vti.mod.gov.yu/ntp/rad2004/34-04/dzin/dzin.pdf
A range of 150 to 250 kbar (roughly 2 to 3 million psi) is given for TNT detonation pressures.
All of this is predicated on the fact that a detonation will develop pressures and temperatures that are highly dependent on the way that the charge is confined, how it is detonated (single or multi-point), etc. etc. which determine how efficiently the available chemical energy is converted to mechanical energy. But the numbers from the above should give you ample information to suggest that equating a steam explosion to TNT based on energy content is a poor comparison.
RE: Steam Explosion and TNT equivalance
I appreciate the references.
RE: Steam Explosion and TNT equivalance
RE: Steam Explosion and TNT equivalance
Just consider the difference between an M80 and a single firecracker. One potentially can kill you outright, the other will simply damage your hand, yet the instantaneous pressure wave velocities at center of detonation are probably identical. A firecracker's explosive material, when not confined in the firecracker simply results in a rather satisfying flash, yet, contains the identical energy stored in a normal firecracker.
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RE: Steam Explosion and TNT equivalance
RE: Steam Explosion and TNT equivalance
To stay on topic, I would like to see a comparison of a steam explosion, black powder, and tnt. I think you would see an increase in speed. Imagine an old cannon using all three. Steam probably wouldn't push as far as black powder, and tnt would probably blow up the cannon.
RE: Steam Explosion and TNT equivalance
rmw
RE: Steam Explosion and TNT equivalance
RE: Steam Explosion and TNT equivalance
http://ww
Here a couple of leads to other furnace explosions.
There was a molten metal vs water steam explosion in Japan several years ago. I haven't been able to locate any information so far.
Also many years ago there was an electric furnace explosion and fire at ACIPCO and there was a debate at the time whether cooling water had started the process.
Anecdotal:
My personal experience with a furnace explosion, hydraulic oil, was with a rocking furnace that I had just finished inoculating. When I reached the end of the charging platform a second I signaled the operator to restart the furnace it blew up. I caught two slugs of molten brass in the back.
RE: Steam Explosion and TNT equivalance
I have gone back to look at he prior engineers analysis and he did not include the hydrogen that is generated from the reaction of water with molten Ti.
So back to the "original" question....even with the hydrogen disassociation from the metal, would this explosion still behave like a chemical TNT explosion? The pressure would be the same, but the velocity of the shock wave will be decreased, right?
Thank you for the JOM reference...I have found that one, but no other furnace explosion references, or articles on this type of reaction (lots on molten metal droplets into water, but no water on a molten metal pool)
The system I am looking at is very small relative to the furnaces referenced in the JOM article. the crucible diameter is 6 inches.
Thank you all again for your comments.
RE: Steam Explosion and TNT equivalance
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RE: Steam Explosion and TNT equivalance
The paper, "Safe Design of Melting Systems for Titanium," was authored by Eldon Poulsen, Timet; Steven C. Stocks, Oremet; Steve Giangiordano, RMI: Eric Jarvis, IMI; and Jim Silvas, Titanium Melt Division, Teledyne Allvac.
http://www.lindahall.org/
RE: Steam Explosion and TNT equivalance
Note:
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RE: Steam Explosion and TNT equivalance
Also, by no means is hydrogen evolution from the puddle going to be the same as a TNT detonation either. The H2 will evolve without a stoichiometric level of oxygen being present, so it will have to mix/diffuse into surrounding air before it can detonate, reducing the blast pressure and velocities obtainable. Again, not to minimize the very real hazard, but trying to point out that equating the energy of a TNT detonation to anything other than high explosives is useless as means of analysis.
RE: Steam Explosion and TNT equivalance
Chris
RE: Steam Explosion and TNT equivalance
RE: Steam Explosion and TNT equivalance
Maytag