On 5/24/2016 12:09 PM, Peter Fairbrother wrote:
On 24/05/16 19:19, Henry Vanderbilt wrote:
Seems to me it might be worthwhile to come at this from the opposite
end: What conditions would be necessary to produce thorough mixing of
the majority of a vehicle's LOX-CH4 propellants, followed by detonation?
And, how unlikely can they be affordably rendered?
You'd need major structural failure with LACK of immediate ignition,
followed by release of the propellants into some sort of containment (a
big pit for the rocket to fall back into?) so they mix in bulk rather
than boil away furiously and disperse (how long might this take in this
theoretical worst-case?) followed by ignition.
Boiling away might be a very bad thing - the cold mixed vapours would
have quite a large density, and also a very large external surface area
- so coupling with the atmosphere would be much greater than in a
mixed-liquid case.
If that went boom as mixed vapours the shock wave would be lower in
terms of maximum shock pressure, but the blast wave would be higher in
total energy and last much longer in the mixed vapours case.
Forget windows breaking, this would push walls over at distances at
which a high-order mixed-liquid detonation would just have people going
"ouch".
In explosions of such size, at close range you're dead anyway - how
doesn't matter to you very much. Especially where atmospheric coupling
is bad, a lot of the total energy is absorbed at close range.
However, at longer ranges your chances of survival would be much worse
with a mixed vapour explosion when atmospheric coupling is good.
Also, it wouldn't matter as much if it was a deflagration or a
detonation either: a deflagration could actually quite easily deposit
slightly more energy at longer ranges.
This is in part what a fuel/air "thermobaric" bomb does.