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can a turbofan burn a kerosene / H2O2 mixture ?

Archibald

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As title say.
Let's take a stock military turbojet such as the J-75.
Can it withstand H2O2 in its kerosene ?

Why such a strange question ? ;D

It's just that I'm currently interested in the Black Horse/ Black Colt / P.R Pathfinder concepts.

They used turbofans and H2O2 in-flight refueling (not all of them, there have been lots of variants from 15 years now)

Btw correct me if I'm wrong

- Seems that kerosene and H2O2 can be mixed into a single tank giving what is called a monopropellant... ???

- when LOX and hydrogen need separated tanks
(I suppose its because these cryogenics fuels have different boiling temperatures ?)
 
L

Lee

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I don't know about burning H2O2 in a jet engine with JP-4 as being different than a monopropellant. Blast propagation can flash back through the fuel lines to the fuel tank. BOOM! :eek: ::) :'( This was seriously considered an *issue* by Clark in his definitive book, Ignition!.
However, try looking at this for a different perspective on the Black Horse theme:

http://uplink.space.com/printthread.php?Cat=&Board=businesstech&main=409143&type=thread

Click on the "Attachment" under the date in the first post.
(I downloaded most of the page and I think the author of that post is WAY overstating 1) his ability to procure the necessary materials to succeed in what he desires to do and 2) that his homemade craft has the required mass ratio to achieve orbit---about 30,000 ft/sec.)
He needs something like beta-titanium and concentrated H2O2. That's something Homeland Security will want to talk to him about.
 

mz

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You can put kerosene in LOX too, it solidifies as white particles. You can burn it in an engine as a monopropellant and it doesn't necessarily back-propagate to explode the tank.
 

Michel Van

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oh boy i start to clean this mess out


H2O2 + catalysts = produces steam and pure oxygen at high temperatures. (over +500°C)
this Hot Steam and O2 mix with Kerosene makes Kaboom
that why is used as Oxidiser and Fuel in Rocket Engine, not in standart military turbojet!
only way to use that stuff is as High Trust Afterburner

More on H2O2 + catalysts here:
http://en.wikipedia.org/wiki/Hydrogen_peroxide#Decomposition
use of H202 as Rocket Oxidiser
http://www.spaceuk.org/htp/htp.htm

so far i know H2O2 (water like) and Kerosene (Ol) do not mix


Oxidiser and Fuel
H2O2 Freezing Point: -1 deg C. Oxidiser Boiling Point: 150 deg C.
LOX Freezing Point: -219 deg C. Oxidiser Boiling Point: -183 deg C.

LH2 Freezing Point: -259 deg C. Fuel Boiling Point: -253 deg C.
Kerosene Fuel Freezing Point: -73 deg C. Fuel Boiling Point: 147 deg C.
(in LOX is freeze to solid ice on bottom of LOX tank)

before some come up with this: No that work also not
Alumizine kerosene aka the metalized kerosene ("Kerosol") by Eugene Sänger
this only high unstable Rocket fuel. nothing for turbojet engine
 

Archibald

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Thank you very much for you answer.
I was more confident in people of this board that's why I posted here ;D

But I'm a bit confused now.

this Hot Steam and O2 mix with Kerosene makes Kaboom
that why is used as Oxidiser and Fuel in Rocket Engine, not in standart military turbojet!

If both engines use H2O2 /kerosene at high temperatures, so why would the turbojet "kabooooom!" and not the rocket ?
I mean why did the Black Arrow didn't exploded in this case ?

Btw I agree that the Black Horse was unrealistic : you won't solve well-known problems of Single-Stage-to-Orbit vehicles with flight refueling only
(otherwise we would have had plenty of them since 30 years and NASA would never have bothered with the X-33)

The author M. Burnside Clapp and USAF probably understood this too, as they quickly changed the design into a two-stage-to-orbit, introducing and expendable upper stage.
This iteration gave the Black Colt, and later the Pathfinder.

Btw Michel if you find easier to explain in french drop me a mail, no worries.
 
L

Lee

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Archibald, quoted: "...this Hot Steam and O2 mix with Kerosene makes Kaboom
that why is used as Oxidiser and Fuel in Rocket Engine, not in standart military turbojet!"
"I mean why did the Black Arrow didn't exploded in this case?"

I only said the fuel/oxidizer monopropellant may back-propagate to the main tank and detonate the whole thing. There are several American patents that describe various kinds of rocket monopropellants, but none that use the same in a turbojet engine. It should work, but excess oxygen may cause corrosion of the exhaust turbines.




Archibald: "The author M. Burnside Clapp and USAF probably understood this too, as they quickly changed the design into a two-stage-to-orbit, introducing and expendable upper stage."

Clapp is famous for mathematically determining that an SSTO would get to orbit with just non-cryogenic kerosene and H2O2. His reasoning was the high density of the mixture(about 1.3 g/cc) would allow for the minimum size vehicle, thus increasing acceleration and reducing overall atmospheric drag. He wrote a paper to that effect which was presented at an AIAA conference, but I can't say I'm convinced unless I see the paper. The AIAA requires one to pay for copies, although it's available to the public from their server.





Michel Van, quoted: "H2O2 + catalysts = produces steam and pure oxygen at high temperatures..."

Absolutely. That's how the German V-2 rocket worked in the turbopump. Burning alcohol in the oxygen for the V-2 engine eliminated some of the compatibility problem(s). But you're right: trying to burn a water-and oil-soluble fuel/oxidizer is a *bad idea*. For example,

2 B5H9 + 5 N2H4 = 10 BN + 19 H2

(Hydrazine is soluble in water and pentaborane-9 is soluble in oil. However, adding methanol to the hydrazine may help, but performance will take a hit. John Clark finally designed a VERY complicated combustion chamber injection head in his experiments, outlined in his book, Ignition!, to compensate for the solubility issue. He got almost the theoretical specific impulse, but it took a lot of work.
Michel Van has a point in saying that oil-water incompatibility is an issue to be overcome.
 

Michel Van

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If both engines use H2O2 /kerosene at high temperatures, so why would the turbojet "kabooooom!" and not the rocket ?
I mean why did the Black Arrow didn't exploded in this case ?

you can see a Rocket engine combustion as constant explosion


turbojet on the other hand is a gasturbin

a lot of Moving parts in combustion chamber
so the only way to use H2O2 /kerosene in Turbojet is as Afterburner in Nozzle
 

Archibald

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Thank you alls.

Physics and mathematics are not my cup of tea as you probably noticed... ;D

His reasoning was the high density of the mixture(about 1.3 g/cc) would allow for the minimum size vehicle, thus increasing acceleration and reducing overall atmospheric drag.

But wouldn't this be negated by the fact that H2O2/ Kerosene combo is low-energy propellant compared to LOX/hydrogen (high energy, but a PITA to stock)?
 

Michel Van

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Archibald said:
Thank you alls.

Physics and mathematics are not my cup of tea as you probably noticed... ;D

His reasoning was the high density of the mixture(about 1.3 g/cc) would allow for the minimum size vehicle, thus increasing acceleration and reducing overall atmospheric drag.

But wouldn't this be negated by the fact that H2O2/ Kerosene combo is low-energy propellant compared to LOX/hydrogen (high energy, but a PITA to stock)?
because LOX/hydrogen has Low density (0.28 g/cc) so need big, very big tanks
was maximise size vehicle, increase overall atmospheric drag.
 

Archibald

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That something very evil...

On one hand, low-energy but dense fuels; on the others hand, high-energy but low-density fuel, needing huge insulated tanks...
Evil, just plain evil!
 
L

Lee

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"...because LOX/hydrogen has Low density (0.28 g/cc) so need big, very big tanks was maximise size vehicle, increase overall atmospheric drag."

Precisely. H2/O2 rocket engines are physically larger and heavier the kerosene-burning engines because H2 has such a low density.





"On one hand, low energy but dense fuels;..."

Well, how about di-acetylene (HC:C:C:CH)? Very low heat of formation and fairly high density.





"...high energy but low-density fuel, needing huge insulated tanks..."

Adding gelled methane to liquid H2 will increase density of the H2 and only slightly decrease specific impulse if used sparingly.





"Evil, just plain evil!"

Physics is physics. "There ain't no free lunch." ;D :mad: ;) ::) :-\
Some tradeoffs are usually needed in the design process of anything.
 

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