[AR] Re: Hydrogen: Fireworks

  • From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
  • To: Arocket List <arocket@xxxxxxxxxxxxx>
  • Date: Thu, 16 Jul 2020 14:54:10 -0400 (EDT)

On Thu, 16 Jul 2020, Keith Henson wrote:

Actually, no, propane is still liquid at the normal boiling point of LOX.
The good news is that they're mostly immiscible -- the two liquids won't
mix much.  The bad news is that they're miscible *enough* that the result
is still explosive.

The one time I made a few milliliters of this mix, it seemed miscible
in that there was no obvious oil/water type separation at one
atmosphere.  I should have done it in a test tube with a strong light
to look for an interface.  But knowing how energetic this stuff is ...

Yeah, it's a great experiment for somebody else to do. :-) Apparently even the pros feel that way -- data on this is scarce, and there's some disagreement about numbers. There *is* general agreement that you get phase separation when propane content goes above a few percent.

One thing I left out of the description of the two-liter bottles is that they capped them and let them warm up. A soda bottle at LOX temperature (or LN2) will take a lot of pressure, probably upwards of 20 atmospheres. That may be enough to make the liquids fully miscible.

Reportedly they're fully miscible at sufficiently high pressures (no surprise), but I don't know if that's enough.

However, a number of years ago on this list, Roger Gregory reported witnessing an informal experiment in an open container that produced an impressively violent explosion. So keeping the pressure low is no guarantee.

Henry

Other related posts:

  1. Home
  2. arocket
  3. Archive
  4. 07-2020