[AR] Re: Hydrogen and oxygen used as pressurizing gasses
- From: David Weinshenker <daze39@xxxxxxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Sat, 12 Dec 2015 10:24:50 -0800
On 12/12/2015 09:57 AM, Henry Vanderbilt wrote:
Some considerations here, in no particular order.
Pressurizing cryo liquid with the same material's gas phase in the short
term suffers not so much from re-liquefaction of the gas, as from
extreme chilling of the gas, thus loss of gas pressure, thus increase in
mass and volume-flow of gas required to keep up pressure.
Of course this isn't such a problem in a pump-fed system (where
a high-pressure liquid supply can be tapped from the pump outlet,
to flow through a regulating valve and heat exchanger to the tank...
at which point the effect of chilling of the pressurizing gas
in the tank would be to increase the required recirculation
flow, rather than the depletion of a consumable supply - the
system won't "run out of pressurant" until it consumes all the
liquid propellant.
(Also the residual vapor mass at liquid depletion is reduced
due to the low tank pressure.)
-dave w
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