[AR] Re: Hydrogen and oxygen used as pressurizing gasses
- From: Ben Brockert <wikkit@xxxxxxxxx>
- To: "arocket@xxxxxxxxxxxxx" <arocket@xxxxxxxxxxxxx>
- Date: Fri, 11 Dec 2015 17:40:32 -0500
On Fri, Dec 11, 2015 at 2:55 PM, Brian Feeney <alaiadesign@xxxxxxxxx> wrote:
Thanks for the feedback! Will hydrogen gas on LH2 work or will it have the
same problem as O2 gas on LOX?
Yes. Though it will be different than LOX, because hydrogen is always
different. Do you have a source for liquid hydrogen? It's not a fluid
I've ever bought. have you worked with it before?
The amount of gas that dissolves into the liquid is a balancing act
between the specific heat of the gas times the temperature difference,
vs. the heat of vaporization and specific heat of the liquid. Gas at
the surface is giving heat to the liquid, with the gas turning to
liquid if it's able to give up enough heat. Eventually the surface of
the liquid is at a temperature where its vapor pressure is equal to
the tank pressure and an uneasy stalemate is reached. Until you shake
the tank. This also means that the liquid quality goes down as the
tank is depleted; expect the injector and possibly plumbing to go two
phase and give weird results at the end of the burn.
Because they're both diatomic gasses, hydrogen and oxygen have very
similar specific heat per volume of the gas. But the hvaps are very
different.
Ben
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