On 22/07/15 01:09, Peter Fairbrother wrote:
On 22/07/15 00:21, Monroe L. King Jr. wrote:
My 2 cents I'm not sure I agree with the conclusions. I think that super
hot AP fire melted everything into pools (what asphalt tarmack is
completely flat?) as the pools cooled toward the end of the fire (which
would have cooled fast as well) the AP crystallized causing the needed
pressure for detonation. Smaller pools first as they cooled faster than
the bigger pool.
AP (and products, even with a little fuel) does not melt-and-flow - it
does melt-and-coagulate a little, a very unusual phenomenon [1] - but it
usually turns into gas before flowing.
It is often said to sublime, but no-one can agree on how, or even what
the products are ..
[1] suppose eg 200 micron crystals, heated slowly, where the excess heat
can dissipate. The crystals start to decompose, and about 30% of the
mass is lost - but what remains of each crystal is like teeny blobs of
AN, all loosely stuck together, like a foam, and the "foam crystal" is
still about the same size as the original crystal.
There is "transient melting" of the original crystals, which allows them
to stick together if conditions are right, leaving a very unusual
substance - it has the original gaps between the original crystals
mostly still intact, but the individual crystals are now sponge-like,
with teeny holes in them.
And the resulting product is 100% AP and unlike ordinary AP, it is
stable to heat, at about 230 C.
This is very weird. AFAIK, no-one knows why this happens.
