Re: scamjets (was Re: ...Mars Rover in Trouble? Or a hoax video?)

I hope you don't mind me top posting, I prefer it.

The development of computer models always follow the research that they are
trying to explain. Especially something that is still half a black art. To
me the proper approach is to go and do it, with a proper tool that allows
the subject to be explored properly. Building very expensive, one shot
experiments to verify our limited understand of the CFD models is not it.

WRT, Fluid Variable Intakes, turbulence is part of the problem, but the
majority of this problem is simply fluid manipulation, not ignition. The
CFD models are probably at a state to handle the majority of the problem,
which could be used to build a vehicle to carry the black art experiments.
Add some physicists, or aerodynamicists with the proper background to
search in the right areas to get the combustion right and come up with the
proper models. If one approach doesn't work quite right, swap out a few
parts and fly the experiment again. Experiments are the proper way to treat
black art subjects, not waiting for the CFD models to come first. Cheap,
easily modified experiments, not expensive one shot wonders.

As, I said earlier, there is a clear path of experimentation from turbojet,
ramjet and scramjet. Push the turbojet past it's normal range, then add the
scramjet running as ramjet and push it past it's normal range, then work on
the transition from ramjet to scramjet and finally start optimizing the
scramjet. The turbojet is running the entire time, providing the maximum
thrust it can, and probably providing almost all it's thrust from the
rocket equation at the end of the run. It's the Fluid Variable Intakes that
allows such a progression, and it's an acceleration type mission profile,
short duration experiments each optimized for acceleration, not endurance.

Throwing away the endurance mission profile requirements totally, in favor
of the acceleration mission profile requirement in the turbojet, ramjet,
and scramjet final designs too. IMO, the two different requirement sets
yield different end results. And personally, hope the endurance
requirements are abandoned...

As to the hypersonic engine mentioned, it's not an extention of the
scramjet, or a hypersonicramjet. The engine I'm talking is probably best
developed from the other end of the atmosphere and would meet the scramjet
somewhere in the middle of the atmosphere. I think an understanding of this
engine and how it works is important to scramjets used in acceleration type
mission profiles. It could also be use to go to the Moon and Mars. Might
even shorten the time to Mars by quite a bit.

Not a Taming of Lions, but more like a child learning to crawl, walk and
finally run.

**
Craig Fink
Courtesy E-Mail Welcome @ WeBeGood@xxxxxxxxx
**


Monte Davis wrote:

You seem to have an exaggerated idea of our mastery of high-energy
fluid dynamics. It has always been *hard* stuff, and for all the
progress in computational FD it remains so. There is a reason why
physicists have been calling turbulence "the work of the Devil" for
150 years; it's where what we now call chaos first forced itself on
their attention, because very small irregularities tend to get big
very fast. There is a reason why predicting hurricane behavior is
tricky, why killing off combustion instability in rocket engines is
still half a black art, why tokamaks keep turning up fascinating new
ways for plasma to kink itself, etc, etc, etc.

It *sounds* cool as can be to shape supersonic->hypersonic inlet flows
with other flows instead of structures, and I'm not saying it can't be
done with enough time and money. But forgive me if I hear in your
optimism the ring of "Taming lions is dangerous, so I'm going to get
this tiger to do it..."

Craig Fink <WeBeGood@xxxxxxxxx> wrote:

Scramjets haven't had Fluid Variable Intakes attached to them yet. As the
speed of a Ramjet increase, so does the compression (area) ratio of the
Inlet. This can be done with Fluid instead of an all variable structure
solution. At the point of instability at the throat, where the air begins
to disassociate, the Fluid is turned off. The normal shockwave at the
inlet throat travels through the engine and out the nozzle, it's now
operating as a Scramjet. All done with the twist of a valve, instead of
complex variable structures.

.

Relevant Pages

  • Re: Hypersonic scramjet transports imminent.
    ... announced completion of a hot flow test on a dual ramjet and scramjet ... hypersonic engine for the Falcon combined cycle engine technology ... the shock waves of its own flight. ... will ignite and speed it up to about Mach 4.8 and if all goes well, ...
    (rec.aviation.military)
  • Re: Hypersonic scramjet transports imminent.
    ... announced completion of a hot flow test on a dual ramjet and scramjet ... hypersonic engine for the Falcon combined cycle engine technology ... the shock waves of its own flight. ... will ignite and speed it up to about Mach 4.8 and if all goes well, ...
    (rec.aviation.military)
  • Re: Brit Scramjet Model Does Mach-8 - New Era of Cheap Sat Launches Near
    ... revolutionary scramjet engine designed by Qinetiq, ... Scientists believe that the scramjet could one day be used to power ... except that the combustion of the fuel and air ... "SABRES" (Synergistic Air-Breathing Rocket Engines). ...
    (alt.politics)
  • Re: Scram Success
    ... Couldn't it reach the necessary velocity to reach space ... Once the scramjet shuts down, ... engine to see it it works before you launch it, ...
    (sci.space.policy)
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