Do you by chance know the serial number or mission for the detonation
incident? I'm finding four probable bulkhead-reversal failures, and
that looks like it might be our Maximum Credible Event for propellant
mixing. If it can lead to detonation in LOX-RP1, LOX-methane is going
to be interesting.
So, yeah, common bulkheads not recommended.
John Schilling
john.schilling@xxxxxxxxxxxxxx
(661) 718-0955
On 5/24/2016 1:07 PM, Henry Spencer wrote:
On Tue, 24 May 2016, Henry Vanderbilt wrote:
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...
One way containment might happen is rupture of a common bulkhead. Some of the Atlas accidents started that way (I don't know if that one reported detonation accident did, but it seems plausible). The Atlas common bulkhead was an extreme case: a thin stainless dome held rigid by higher pressure underneath, with LOX above and kerosene below. If pressurization got messed up, the bulkhead could invert, which usually ruptured it... and then you had heavy LOX pouring downward into lighter kerosene, with the outer shell of the tanks still intact (until LOX boiling burst it), a situation that could produce considerable mixing even with the LOX boiling and the kerosene freezing.
Common bulkheads are a bit sporty in general, but they seem particularly undesirable with readily-miscible propellants, like peroxide/alcohol or LOX/methane.
One might want to assign a higher TNT equivalent to LOX/methane in common-bulkhead tanks.
Henry