[AR] Re: P&W GTF
- From: Craig Fink <webegood@xxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Sat, 4 Apr 2020 07:46:19 -0500
On Sat, Apr 4, 2020 at 12:55 AM Henry Spencer <hspencer@xxxxxxxxxxxxx>
wrote:
On Fri, 3 Apr 2020, ken mason wrote:
Then I'm guessing a fundamental breakthrough in battery/energy
storage tech. will be needed, assuming motors are scalable...
Alas, I recall seeing an old article about electric-car technology, which
reached about the same conclusion: (roughly) "we've got most of it under
control, but we could really use a breakthrough in batteries". That's
still pretty much where electric cars are today. That article was from
circa 1910. So, holding of breath not recommended... :-)
With electrics like a train, the electricity generation and use are
separated, so each can be optimized or designed in there own way. I
wouldn't get so hung up on battery, they are just the easiest step along
the path. The fact that Rocket Lab is dropping a set of batteries in the
second stage is reasonable and very simple to gain a bit of performance.
Rocket Lab's abandonment of disposable rockets (1st stage) is probably the
more important step. So it might be reasonable at some point in the future
to start tackling the battery part and move to some other electricity
generators. My favorite is a gas generator turbo-electric generator, and
since we are talking about space travel, there are several options of what
to do with the spent gas. Exhaust it thru small low performance rocket
being the simplest like current rocket engines do, second stage is in a
vacuum so performance is always reasonable with no back-pressure. Exhaust
it into the tank of super-chilled propellant, use that giant heat sink
called propellant. Probably much easier and less complex than building a
full-flow staged combustion cycle engine. If it's a passenger rocket with a
destination like ISS, why exhaust the spent propellant at all. Which brings
us back to Hydrogen, the most compact, lightest fuel/battery of all. Water,
the easiest most useful spent fuel/battery exhaust. Carbon Dioxide, the
hardest exhaust to try to collect and store. Where there are humans, water
will always be in demand. I could go on and on about optimizing various
things when the power generation is separated from the power usage, like a
train, especially if one intends to fly to orbit in the atmosphere.
The AI designed single piece rocket is interesting, makes for a simple
full-flow "Gas Generator" cycle engine. Add another heat exchanger jacket
to the outside of the Thrust Chamber to liquefy the turbine exhaust. Add
and integrated Electric Water Pump to bring the now liquid turbo-generator
exhaust back up to pressure and inject it back into thrust chamber. Give
the AI a little more to optimize. So, now there is a single piece thrust
chamber with integrated pumps and generator, the part count is tiny. Plus,
if you spin an electric pump backwards, it can act as a valve keeping the
liquid in the tank while letting a bit of gas pre-chill the engine,
potentially eliminating some valves while simplifying controls. I could go
on and on here..... Time to turn the AI loose and let it optimize...
--
Craig Fink
WeBeGood@xxxxxxxxx
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