[AR] Re: PEPCON AP explosion report

  • From: Geoff Huber <geoff.huber@xxxxxxxxx>
  • To: arocket@xxxxxxxxxxxxx
  • Date: Mon, 20 Jul 2015 14:38:53 -0700

Wasn't Piper hired after Pepcon to research the cause?

On Mon, Jul 20, 2015 at 2:31 PM, Peter Fairbrother <zenadsl6186@xxxxxxxxx>
wrote:

On 20/07/15 22:00, Anthony Cesaroni wrote:

...and pressure. Remember AP is not just an oxidizer, it's a
monopropellant. Once you get it above ~700 psi, it will run quite
nicely on its own with a theoretical Isp of around 170.

Anthony.


Yes - and it's not just gas pressure.

If you have a big pile of AP the crystals press against each other,
compressing them - even though there is air or gas at atmospheric pressure
surrounding the crystals, the crystals at the bottom of the pile are still
under pressure.

Then it gets hot .. and the surface melts, so product gas is trapped and
the gas pressure and temperature rises .. and polythene containers melt,
adding fuel to the mess .. and the mess slumps when the containers melt,
increasing average density .. and AP itself melts, increasing density yet
again, and making shock wave transmission easier, more efficient, and
faster .. and the mass involved is such that the available radius is very
large, and shock waves are near-planar, making energy transmission more
efficient .. and BOOM!


Ammonium nitrate does much the same too.


-- Peter Fairbrother






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