Well, on the plus side, He is gas at O solid temps so you can cool with a gas
loop welded to the tank exterior, inside external insulation. You have to have
a deep cryo gas disconnect but that could be a guillotine on two metal feed
lines.
Sent from my iPhone
On Nov 7, 2016, at 8:59 PM, Henry Spencer <hspencer@xxxxxxxxxxxxx> wrote:
On Tue, 8 Nov 2016, Jake Anderson wrote:
Do you actually need to move the lox? if you are trying to keep it cold
could you perhaps do that through the skin of the vehicle/tank? IE put a
panel in good thermal contact with the tank (at the top of the fill level
perhaps to help with stratification etc) with a LN2 loop running through
it...
That's just a heat exchanger by another name, alas. Building a good heat
exchanger that will break in the middle on command is likely to be hard; the
panel won't be a perfect fit to the skin, and any gap not only will ruin its
effectiveness as a heat exchanger, but also will fill in with ice pretty
quickly, unless you add a helium purge to keep air out...
It's not easy to make that sort of thing work well. The original Centaur
jettisoned the insulation on its LH2 tank at startup, but that led to the
same problems with icing and purging, and fixes added so much mass that
Centaur performance actually *increased* when they switched to foam
permanently bonded to the tank.
The simpler way to put in a good heat exchanger is to make it a permanent
part of the tank. But good heat exchangers tend to be heavy.
Moving the LOX actually is the easy way, because it lets you put all the
heavy equipment on the ground side of the disconnects.
Henry
