[AR] Re: ALASA canceled because... Mixed Mono

  • From: Lloyd Droppers <ldroppers@xxxxxxxxx>
  • To: arocket@xxxxxxxxxxxxx
  • Date: Sat, 5 Dec 2015 09:53:57 +1300

Yes, saying that a liquid N2O has a 1/4" critical diameter means that a
tube larger that 1/4" will propagate a detonation wave while a smaller tube
can damp the detonation wave depending on the material, length, etc. 1/4"
is actually a reasonable size as far as critical diameters for rocket
monopropellants. For Ref 90%HTP is 1.0" critical diamete
<http://permalink.lanl.gov/object/tr?what=info:lanl-repo/lareport/LA-UR-10-01464>r,
Nitromethane is 0.1"
<http://scitation.aip.org/content/aip/proceeding/aipcp/10.1063/1.2263489>,
and I couldn't find anything else quickly.

I think that you might be setting up a false dichotomy in thinking gaseous
nitrous is the real bogeyman, as liquid nitrous is still a monopropellant
and potentially dangerous if not handled with care. You have probably seen
this but SPL has a nice intro on Nitrous safety
<http://www.spl.ch/publication/SPL_Papers/N2O_safety_e.pdf>.

Lloyd

On Sat, Dec 5, 2015 at 7:24 AM, Paul Mueller <paul.mueller.iii@xxxxxxxxx>
wrote:

Thanks for the info and I'll try to educate myself. Meanwhile, does this
mean that a 1/4" tube full of liquid nitrous could propagate a detonation
wave due to dissociation (presumably the only energy source that could
cause a detonation wave)? This seems to contradict my previous
understanding that it is very difficult to have a dissociation reaction in
liquid nitrous. Gaseous nitrous is the real boogey-man here. Am I up in the
night?

Paul M

On Fri, Dec 4, 2015 at 11:08 AM, George Herbert <george.herbert@xxxxxxxxx>
wrote:


You really want Paul Coopers grad level textbook "Explosives Engineering".

George William Herbert
Sent from my iPhone

On Dec 4, 2015, at 9:54 AM, Ed LeBouthillier <codemonky@xxxxxxxxxxxxx>
wrote:

Paul Mueller said

Yeah, I'm not familiar with the "critical diameter" and what it means
that it is about 1/4" for liquid nitrous oxide.

The critical diameter is the diameter at which a detonation can proceed
down a tube.
Smaller than that, the detonation should not propagate, large than
that, it should.

It's touched on here:

https://en.wikipedia.org/wiki/Explosive_material

and is more detailed here:


https://books.google.com/books?id=5P-mCAAAQBAJ&lpg=PA285&ots=42Lfa7DirE&dq=critical%20diameter%20detonation&pg=PA285#v=onepage&q=critical%20diameter%20detonation&f=false





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