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Author Topic: Skylon Spaceplane  (Read 84573 times)

Offline Flyaway

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Re: Skylon Spaceplane
« Reply #195 on: September 25, 2017, 04:07:55 pm »
Awarded DARPA Contract to Perform High-Temperature Testing of the SABRE Precooler

CASTLE ROCK, Colorado – September 25, 2017

Reaction Engines Inc., the U.S. subsidiary of Reaction Engines, today announced that it has received a contract from the U.S. Defense Advanced Research Projects Agency (DARPA) to conduct high-temperature airflow testing in the United States of a Reaction Engines precooler test article called HTX. The precooler heat exchanger is a key component of the company’s revolutionary SABRE air-breathing rocket engine and has the potential to enable other precooled propulsion systems. The primary HTX test objective is to validate precooler performance under the high-temperature airflow conditions expected during high-speed flights up to Mach 5.

“We have been greatly encouraged by the increasing interest in our technology’s potential and are thrilled to embark on our first U.S. government contract with DARPA for HTX,” said Dr. Adam Dissel, President of Reaction Engines Inc. “Full-temperature testing of the precooler will provide the most compelling near-term proof of the technology’s potential to accelerate the future for high-speed air-breathing systems.”

The HTX precooler test builds upon previous successful ground tests of the precooler technology conducted at ambient environmental conditions in the United Kingdom. These previous tests validated precooler design methodology, manufacturing techniques, and test operations plans.

To support HTX testing, Reaction Engines is constructing a new high-temperature airflow test facility, located in Colorado. Under the DARPA program, the company aims to establish the facility’s capability to provide airflows in excess of 1800°F (1000°C), analogous to air-breathing flight above Mach 5, and then conduct the testing of a Reaction Engines-supplied precooler starting in the spring of 2018.

Mark Thomas, Chief Executive Officer of Reaction Engines, commented, “The announcement of DARPA’s contract is fantastic news and provides us with the opportunity to demonstrate our innovative heat exchanger capability in the world’s largest aerospace market. This will accelerate our development efforts and strengthen key relationships.”

Reaction Engines has world-leading expertise in the design and manufacture of compact, lightweight heat exchangers capable of cooling airstreams from over 1800°F to -240°F (1,000°C to -150°C) in less than 1/20th of a second. Developed for the high-speed SABRE engines, the precooler heat exchangers prevent engine components from overheating at high flight speeds and thereby could enable new classes of vehicles and operational possibilities.

END

https://www.reactionengines.co.uk/reaction-engines-awarded-darpa-contract-to-perform-high-temperature-testing-of-the-sabre-precooler/

Offline steelpillow

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Re: Skylon Spaceplane
« Reply #196 on: September 26, 2017, 11:02:41 am »
Guess they'll be running a precooler in reverse to create an adequate preheater for the test airflow ;)
Cheers.

Offline merriman

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Re: Skylon Spaceplane
« Reply #197 on: September 26, 2017, 11:31:02 am »
Guess they'll be running a precooler in reverse to create an adequate preheater for the test airflow ;)

They could do what the PLUTO people did at Jack-Ass Flats. Or aim the south-end of an after-burning engine into the maw of the pre-cooler. Or have the crew wolf down bean-burritos 30-minutes before test.

David
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Offline sferrin

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Re: Skylon Spaceplane
« Reply #198 on: September 26, 2017, 12:01:03 pm »
Guess they'll be running a precooler in reverse to create an adequate preheater for the test airflow ;)

They could do what the PLUTO people did at Jack-Ass Flats. Or aim the south-end of an after-burning engine into the maw of the pre-cooler. Or have the crew wolf down bean-burritos 30-minutes before test.

David

Imagine the cooler required to take the exhaust from say, an F414 in afterburner, and turn it into liquid.  :o
"DARPA Hard"  It ain't what it use to be.

Offline TomS

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Re: Skylon Spaceplane
« Reply #199 on: September 26, 2017, 12:13:23 pm »
Imagine the cooler required to take the exhaust from say, an F414 in afterburner, and turn it into liquid.  :o

Not quite that cold -- it's about 40C above the liquefaction point.  But yeah, it's pretty heroic.  Keeping it from icing up seems like the worst part.  Ice blocking channel in the precooler could cause serious problems, so they have to dry the air as well as chill it.




Offline steelpillow

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Re: Skylon Spaceplane
« Reply #200 on: September 27, 2017, 01:12:52 am »
Imagine the cooler required to take the exhaust from say, an F414 in afterburner, and turn it into liquid.  :o

Not quite that cold -- it's about 40C above the liquefaction point.  But yeah, it's pretty heroic.  Keeping it from icing up seems like the worst part.  Ice blocking channel in the precooler could cause serious problems, so they have to dry the air as well as chill it.

As I understand it, the oxygen in the air will liquidise, but not the nitrogen. What comes out the back is a kind of gassy slush. Jet exhaust would have high carbon dioxide and water content and that would solidify into both ordinary and "dry" ice well above these temperatures. Without knowing the detailed test regime, it probably needs a heat exchanger to keep combustion gases out of the precooler. Either that, or use an incandescent electric heater.

My main concern with bean-burritos, as suggested above, is that the very thin tubes of the precooler might curl up in disgust.
Cheers.

Offline TomS

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Re: Skylon Spaceplane
« Reply #201 on: September 27, 2017, 03:29:12 am »
No.  Oxygen liquifies at -183C, so again, SABRE doesn't get quite cold enough.  I think people are confusing this with earlier liquid air cycle engines (LACE).  SABRE specifically is trying to avoid the problems of dealing with liquifying the airflow, so it "only" chills down to -150C.

Offline sferrin

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Re: Skylon Spaceplane
« Reply #202 on: September 27, 2017, 05:20:32 am »
Guilty.  I thought it was a LACE engine.  :-[  I thought the plan was to liquefy air on the way up to use at high altitude / in space where there isn't any.
"DARPA Hard"  It ain't what it use to be.

Offline AndrewN

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Re: Skylon Spaceplane
« Reply #203 on: September 27, 2017, 08:55:00 am »
Reaction Engines does have a "secret sauce" method of eliminating the blocking of the pre-cooler from frozen moisture and other stuff. They won't talks about the details but it is supposed to involve the injection of Methanol into the airstream around the cooler.
By day, a mild mannered teacher of computing.
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Offline Zootycoon

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Re: Skylon Spaceplane
« Reply #204 on: September 27, 2017, 03:26:49 pm »
-150C is the pre-cooler outlet temperature for the Sabre 3 thermodynamic cycle. Reaction Engines latest Sabre 4 thermodynamic cycle doesn't necessarily need operate this low. In fact Richard Varvil has even hinted that the 4  can run on LCH4 (-161C) in place of the LH2 which has the pre-cooler deliveries air at maybe -100C or  higher. The real advantage of LCH4 is the energy density which is just over twice that of LH2.This means the airframe is smaller I.e lighter, for the same payload or range.

Offline steelpillow

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Re: Skylon Spaceplane
« Reply #205 on: September 28, 2017, 12:55:07 am »
No.  Oxygen liquifies at -183C, so again, SABRE doesn't get quite cold enough.  I think people are confusing this with earlier liquid air cycle engines (LACE).  SABRE specifically is trying to avoid the problems of dealing with liquifying the airflow, so it "only" chills down to -150C.

The phrase "cooled to the point of liquefaction" is also used to describe this stage of the engine cycle. It means something fairly specific to a physicist, denoting the temperature at which the fluid liquidises. During liquefaction, the temperature does not change but the fluid gets rid of its latent heat of evaporation. The temperature throughout this period of condensation remains at " the point of liquefaction". If as you say "SABRE doesn't get quite cold enough" then this is not in fact the point of liquefaction and somebody is misleading us somewhere.
Exact temperatures are only a rough guide, as the conditions at the compressor face are far from standard atmospheric pressure and a nice, sealed condensation vessel.
The relevant detail seems to have vanished from the RE web site, so we shall just have to wait and see what the truth really is.
Cheers.

Offline SteveO

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Re: Skylon Spaceplane
« Reply #206 on: October 03, 2017, 10:45:11 am »
Not much on the Reaction Engines website about Skylon or space exploration anymore  :(

You can hardly see Skylon against the black of space and behind(!!) the header on the vehicles page! Oh well, at least work on the Sabre engine is progressing. SpaceX will have to do in the meantime  :D

Found this here though - https://www.reactionengines.co.uk/careers/life-at-rel/

Offline FighterJock

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Re: Skylon Spaceplane
« Reply #207 on: October 04, 2017, 03:26:35 am »
Not much on the Reaction Engines website about Skylon or space exploration anymore  :(

You can hardly see Skylon against the black of space and behind(!!) the header on the vehicles page! Oh well, at least work on the Sabre engine is progressing. SpaceX will have to do in the meantime  :D

Found this here though - https://www.reactionengines.co.uk/careers/life-at-rel/

Interesting find SteveO, another design variant of Skylon that Reaction Engines are investigating, or just a design exercise?

Offline hesham

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Re: Skylon Spaceplane
« Reply #208 on: October 04, 2017, 05:25:49 am »
Nice find Stevo.

Offline Moose

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Re: Skylon Spaceplane
« Reply #209 on: October 04, 2017, 08:29:28 am »
Nice find, SteveO.

Wonder if that's a further exploration of the A2/SCIMITAR concepts rather than Skylon/SABRE.