[AR] Hindenburg Syndrome (Re: Re: Embry-Riddle Prescott Liquid Rocket Engine Hot-fire)
- From: Craig Fink <webegood@xxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Tue, 11 Jun 2019 11:16:57 -0700
This some sort of Hindenburg Syndrome!
https://en.wikipedia.org/wiki/Hindenburg_disaster
Definition, Hindenburg Syndrome, the irrational fear of Hydrogen.
On Tue, Jun 11, 2019 at 5:14 AM Terry McCreary <tmccreary@xxxxxxxxxxxxxxx>
wrote:
Very rong. "Order of magnitude" = factor of ten. Optimal sea-level
specific impulse of LH2-LOX is around 450 s, RP1-LOX is around 260. Not
even a factor of two.
In Air, there is no LOX, just hot Oxygen in the air. That is what I was
talking about as an Order of Magnitude.
https://en.wikipedia.org/wiki/Specific_impulse#/media/File:Specific-impulse-kk-20090105.png
Most of the Theoretical Maximum for Hydrogen using Air isn't even on the
graph from Liftoff to Mach 6.
A quart of RP-1 weighs about two pounds. A quart of LH2, less than three
ounces. For a given mass of O2, you need about *five* times the volume of
LH2 compared to the volume of RP-1 needed, to reach that optimum
performance. That's a biiiig fuel tank.
Yes, the tanks are an order of magnitude bigger and has to be taken into
account. Since 2 pounds of RP-1 has the same energy as 1 pound of LH2, it
only takes 6 liter tank. Ok, half an orders of magnitude bigger tank, no
problem.
In 42 years of teaching college/university chemistry, everything from
chemistry-for-poets-and-football-players up to grad courses, I've never
used *gaseous* hydrogen. In fact, I'm not sure I've ever seen a tank of H2
in the chem storage room. It's avoided unless absolutely necessary (e.g.,
hydrogenation reactions). And that's for the gas. LH2 multiplies the
hazards and the difficulties enormously.
You've just described the problem, no access to use the only fuel that can
give an Order of Magnitude better performance in Air Breathing engines and
Air Breathing Rockets. Yet, we are almost to the point where LN2 is
everywhere. Even a Top Ten list for Liquid Nitrogen accidents
https://www.youtube.com/watch?v=ms1AzNr0wVc
But if I look for the Top Ten list for Liquid Hydrogen accidents, what do I
get?
https://www.youtube.com/watch?v=7bFJK5kU_UQ
A 60 year old video of an intentional test, that's it.
https://youtu.be/7bFJK5kU_UQ?t=139
50 tests, no detonations occurred.
https://youtu.be/7bFJK5kU_UQ?t=215
The four guys caring the 50 gallon drum of boiling Liquid Hydrogen, I guess
the drum is heavy because it sure wasn't the hydrogen.
No detonation, Thermal Flux of only 10%, 30 seconds until it evaporated.
https://youtu.be/7bFJK5kU_UQ?t=369
JP-4 and Gasoline comparison, Thermal Flux is 12X that of hydrogen and
burned 14X longer.
https://youtu.be/7bFJK5kU_UQ?t=440
They had to use a high explosive detonator and intentionally mix it
properly in a balloon to get it to detonate. Just a spark and it just
burns, no detonation.
https://youtu.be/7bFJK5kU_UQ?t=700
Conclusion, Liquid Hydrogen is safer to handle than...
Is LH2 a great fuel? Of course, in theory.*** Handling it and overcoming
the many difficulties makes it a lot less 'great'. If I was involved in a
project using liquids, LH2 would stay inside the reference books. ;-)
As to potential...why mess with LH2 at all? Work out a way to stabilize
liquid monatomic hydrogen and Bob's your uncle. :-)
Usually we call it plasma when the monatomic hydrogen. Solid, Liquid, Gas,
Plasma.
***"In theory there is no difference between theory and practice. In
practice...there is." -- Jan L. A. van de Snepscheut
In Practice, which would you rather clean up a LH2 spill, Gasoline spill,
or JP-4 spill?
--
Craig Fink
WeBeGood@xxxxxxxxx
On 6/11/2019 12:59 AM, Craig Fink wrote:
On Mon, Jun 10, 2019 at 9:01 AM Charlie Garcia <dragonrider.hhcc@xxxxxxxxx>
wrote:
Craig,
LH2 does not have several orders of magnitude of capability over other
potential propellants.
Yeah, only one.?. Sound wright?
--
Dr. Terry McCreary
Professor Emeritus
Murray State University
Murray KY 42071
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