No one's mentioned a slurpee of liquid hydrogen and fine powder solid
oxygen. Is a pad failure of a Delta 4 any worse than a Falcon heavy?
Brisance is what shatters things like concrete non necessarily total
calories/joules released.
Ken
On Sat, Jul 2, 2022 at 8:46 AM Henry Vanderbilt <hvanderbilt@xxxxxxxxxxxxxx>
wrote:
On 7/1/2022 9:52 PM, Henry Spencer wrote:
On Fri, 1 Jul 2022, willsrw@xxxxxxxxx wrote:I seem to recall that the canonical worst-case for a LOX/CH4 (quite
I’m surprised the conversion is assumed to be one to one. A one to
one conversion (propellant to TNT equ) means 100% mixing to a perfect
mixture ratio throughout the entire volume of propellant.
No, not nearly -- methane's heat of combustion (complete combustion,
oxygen included in mass, but assuming water vapor produced remains
vapor) is 10.0 MJ/kg, while nominal TNT energy output is about 4.6
MJ/kg. Even considering that a typical propellant mix doesn't contain
enough oxygen for complete combustion, LOX/CH4 is quite a bit more
powerful than an equivalent mass of TNT. Perfect mixing would yield
close to 200%.
Difficult to do.
But much less difficult than for LOX/LH2 or LOX/kerosene, where the
large temperature difference gets in the way. That's why people are
wary of LOX/methane, in the absence of large-scale tests -- good
mixing is much more plausible when the two liquids are at about the
same temperature and are fully miscible.
mutually soluble) launcher explosion is launch from a pad with a large
flame pit or trench, propulsion failure shortly after liftoff causing
booster to fall back onto the pad, either directly into the flame pit or
the propellant then drains into the flame pit, then considerable mixing
takes place in the big tub of propellant before any ignition. Big
Badda-BOOM! Roughly 50% of the total propellant-load potential
explosive yield seems a reasonable first approximation for such an event.
The scenario came up in discussion here, in fact (could we have thought
of it first? Seems unlikely, but you never know.) In any case, planned
launch pads for LOX/CH4 boosters do now tend to lack large flame
trenches or pits.
Mind, a common-bulkhead failure between LOX and CH4 tanks could produce
something similar in flight. Nobody seems to be pushing for
common-bulkhead LOX/CH4 storage either, oddly enough.
Henry
