USAF + UK's Reaction Engines for hypersonic/single stage to orbit engine

[Umfriend]

Yes, that's what I thought. I'd buy it.

[cjolley]

Very interesting.
I wonder why the Helium working fluid instead of just using the hydrogen directly in the heat exchanger?

[Dr Mordrid]

Helium is often used as a working fluid or gas in rockets because it is inert, has a high thermal conductivity, and a low solubility, boiling point, and density.

The thermal condictivity is handy in the precooler and heat exchangers. When used with LH2 their boiling temps are only about 10°C apart. When starting rocket engines helium gas is used to pressurize the fuel and oxidizer tanks, be they pressure fed engines / thrusters or turbopumped. Etc. etc.

With SABRE helium is the material of choice because it fits the requirements and is already there for other purposes.

[Dr Mordrid]

AFRL = US Air Force Research Laboratory

Cutting metal. The front end precooler of the engine has been tested. They expect a SABRE to fly in a testbed by 2020.

Capabilities
Mach 5 high altitude cruise:
Fly anywhere in the world in 4 hours
Efficient sub-sonic and hypersonic cruise modes

Low-cost reusable space access
Aircraft-like access to space
Operates from runway to orbit and back
Order of magnitude reduction in cost vs. existing technology
400 x improved reliability
Responsive access to space

Reaction Engines Ltd....

AFRL Review Finds Skylon’s SABRE Engine Theoretically Viable

OXFORDSHIRE, England (Reaction Engines PR) — Reaction Engines Ltd. is pleased to announce that analysis undertaken by the United States’ Air Force Research Laboratory (‘AFRL’) has confirmed the feasibility of the Synergetic Air-Breathing Rocket Engine (‘SABRE’) engine cycle concept.

The analysis was undertaken by AFRL as part of a Cooperative Research and Development Agreement (‘CRADA’) with the Air Force Research Laboratory’s Aerospace Systems Directorate (AFRL/RQ). These investigations examined the thermodynamic cycle of the SABRE concept and found no significant barrier to its theoretical viability provided the engine component and integration challenges are met.

Reaction Engines Ltd. and AFRL are now formulating plans for continued collaboration on the SABRE engine; the proposed work will include investigation of vehicle concepts based on a SABRE derived propulsion system, testing of SABRE engine components and exploration of defence applications for Reaction Engines’ heat exchanger technologies.

AFRL/RQ program manager Barry Hellman stated – “The activities under the CRADA have allowed AFRL to understand the SABRE engine concept, its pre-cooler heat exchanger technology, and its cycle in more detail. Our analysis has confirmed the feasibility and potential performance of the SABRE engine cycle. While development of the SABRE represents a substantial engineering challenge, the engine cycle is a very innovative approach and warrants further investigation. The question to answer next is what benefit the SABRE could bring to high speed aerospace vehicles compared to other propulsion systems. Although application of the SABRE for single stage to orbit space access remains technically very risky as a first application, the SABRE may provide some unique advantages in more manageable two stage to orbit configurations. Furthermore, the heat exchanger technology also warrants further investigation for applications across the aerospace domain.”

Sam Hutchison, Director of Corporate Development at Reaction Engines Ltd commented – “The confirmation by AFRL of the feasibility of the SABRE engine cycle has further validated our team’s own assessment and conviction that the SABRE engine represents a potential breakthrough in propulsion that could lead to game changing space access and high speed flight capability. We look forward to continued collaboration with AFRL”.

SABRE is an innovative class of aerospace propulsion that has the potential to provide efficient air- breathing thrust from standstill on the runway to speeds above Mach 5 (4,500mph) in the atmosphere – twice as fast as jet engines. The SABRE engine can then transition to a rocket mode of operation for flight at higher Mach numbers and space flight. Through its ability to ‘breathe’ air from the atmosphere, SABRE offers a significant reduction in propellant consumption compared to conventional rocket engines which have to carry their own oxygen – which is heavy. The weight saved by carrying less oxygen can be used to increase the capability of launch vehicles including options for high performance reusable launch vehicles with increased operational flexibility, such as horizontal take-off and landing. Additionally, the SABRE engine concept could potentially be configured to efficiently power aircraft flying at high supersonic and hypersonic speeds.

SABRE engine




LAPCAT A2

[Dr Mordrid]

Well, well, well....the veil lifts

http://www.aviationweek.com/technology/reaction-engines-reveals-inner-secret-sabre-propulsion-technology

Reaction Engines Reveals Inner Secret Of Sabre Propulsion Technology

The development of a single-stage-to-orbit launch capability has been the Holy Grail to many since the dawn of the space age.

Yet achieving orbit in one stage with conventional rocket power is completely impractical and, despite decades of research into alternate concepts, no workable solutions have been found. It is no surprise, then, that for years the space community has been highly skeptical of claims from a British-based developer, Reaction Engines, that it had discovered an answer with a hybrid air-breathing rocket system.

But after endorsements of the basic technology from the European Space Agency and, more recently, the U.S. Air Force’s Research Laboratory, the company’s synergetic air-breathing rocket engine (Sabre) concept is being taken far more seriously. Designed to power a vehicle from a standing start to Mach 5.5 in air-breathing mode, and from the edge of the atmosphere to low earth orbit in pure rocket mode, the Sabre engine and heat exchanger at the heart of the design is attracting widespread interest for potential application on a range of atmospheric and space vehicles.

With patents pending, and negotiations with new industrial partners apparently at an advanced stage, Reaction Engines has made the surprise decision to unveil the first details of the critical technology at the core of its hybrid hypersonic propulsion system.

A fundamental enabler of the concept is a complex heat-exchanger system made up of miles of fine tubing which allows oxygen to be taken directly from the atmosphere for use as fuel. The system chills incoming air from more than 1,000C, to -150C in less than 1/100th of a second before passing the pre-cooled air through a turbo-compressor and into the rocket combustion chamber, where it is burned with subcooled liquid hydrogen. However, until now the means by which the system does this without clogging up the pre-cooler with ice was a closely guarded company secret.

“It is pretty mind-bending stuff,” says Reaction Engines technical director and chief designer, Richard Varvill. Speaking at the American Institute of Aeronautics and Astronautics International Space Planes and Hypersonics conference here, he says the system counters the frost which precipitates out of the air as it becomes saturated with increasing relative humidity during the rapid cooling process. The precipitation “looks like the white feathery frost you’d see on a cold winter’s day. Unfortunately, that frost is sufficiently mechanically strong that it can bridge the gaps between the tubes and will block the matrix solid in about 3 sec. flat if you don’t do anything about it.

“So—surprise, surprise—we use an anti-freeze, and in this case it is methanol. But we use the methanol in a rather sophisticated way with the objective of minimizing the amount you need. Also we don’t want to spray the methanol in and leave it in the air flow because we are actually cooling down the air to the point at which the methanol would freeze itself,” he says.

To do this, Reaction Engines has “borrowed a trick from the chemical process industry,” says Varvill. “We inject the methanol at one of the coldest points, and we effectively get the mix of water and methanol to flow forward in the matrix—against the direction of the airflow.” He concedes this seems counterintuitive, but explains the system generates an effective reverse flow by catching the water-methane mix and reinjecting it further upstream. “We have multiple injection and extraction points in the matrix, but the overall effect is the mix of methanol and water is actually flowing forward in the matrix against the airflow direction.”

The reasoning, he says, is that the condensate composition at the cold end of the matrix is nearly all methanol and, as it flows forward, the methanol picks up the water. “At the inlet [of the matrix] it is nearly all water so the composition is more methanol-concentrated at the cold end than it is at the warm end," Varvill says. "That then reduces because you have extracted most of the water at the warm end, and that reduces the absolute amount of methanol you need to throw into the pre-cooler to stop it freezing.” Also, because the amount of liquid water reduces so does the relative humidity. “Eventually you end up with a situation where you have extracted all the water vapor as liquid from the airflow and that leaves you essentially with dry air below 215K. The partial pressure of the water vapor at this point is so low that you can allow it to pass through the heat exchanger and it does not freeze.”

Varvill adds that the difficult task of turning this into engineering reality was achieved by experimenting using a wind tunnel specially adapted with an injection and catchment system. Tests of the frost-control system have demonstrated its ability to maintain stable operating air temperatures of -80C and below simultaneously with the pressure drop across the pre-cooler matrix.

Reaction Engines decided to go public on the frost-control technology because of pending patent applications. “The trigger for patenting was the awareness that to execute this program we are going to have to involve other companies,” says Mark Thomas, the former chief engineer for technology and future programs at Rolls-Royce and now managing director at Reaction Engines. “You can’t keep trade secrets very long in that situation, so it is better to be protected formally and legally on the clever stuff.”

Ice-clogging in the Sabre’s pre-cooler is prevented by injecting methanol that is then collected and re\injected in a mixture with water further upstream. Credit: Guy Norris/AW&ST

[Umfriend]

Wow. I do not get that at all. How one could get a mixture of methanol and water to go one way while all else goes the other. And then extract that mixture while leaving the rest flow differently? Somthing like:

_____>_ _<_________________<
| | | |
---OUT 3 ->- IN 3 OUT 2 ->- IN 2 OUT 1 ->- IN 1
| | | |
---<----------------------------< ---------->
---------------> AIRFLOW --------------------------------->

And after intake 3, split methanol and water and re-use the methanol?

Dang, the editor takes out spaces....

[Dr Mordrid]

The methanol must be under a much higher pressure.

This would be wild in the SR-72, 6th Generation fighter and Next Generation Bomber.

NASASpaceFlight thread

http://forum.nasaspaceflight.com/ind...msg1404050#new

Patent docs

http://forum.nasaspaceflight.com/ind...attach=1042094

http://forum.nasaspaceflight.com/ind...attach=1042095

http://forum.nasaspaceflight.com/ind...attach=1042096

[Dr Mordrid]

Jennifer DiMascio @jbdimascio
Reaction Begins Building U.S. Hypersonic Engine Test Site by @AvWeekGuy http://aviationweek....ngine-test-site via @aviationweek
11:07 AM - Dec 18, 2017

Press release

Reaction Engines Begins Construction of High-Temperature Airflow Test Facility in Colorado

WATKINS, CO December 18, 2017

Reaction Engines, Inc. has begun construction of a new high-temperature airflow test facility where it plans to validate the performance of its precooler heat exchanger technology, an enabler of its revolutionary SABRETM engine. Located at the Front Range Airport near Watkins, Colorado, the test facility will be capable of exposing the precooler test article (HTX) to high-temperature airflow conditions in excess of 1800°F (1000°C) that are expected during high-speed flights up to Mach 5.

Reaction Engines, Inc. recently received a contract award from the Defense Advanced Research Projects Agency (DARPA) to conduct the HTX tests, which are designed to build upon previous successful testing of the precooler heat exchanger at ambient temperature conditions.

This new test facility shows our commitment to rapidly prove our precooler technology in the most compelling test campaign possible, said Dr. Adam Dissel, President of Reaction Engines Inc. The facilitys ability to deliver controlled temperature profiles over flight-like run durations at significant airflow represents a unique capability that can fill additional testing demand beyond HTX.

The project is an additional investment by Reaction Engines into ground test facilities. The company is progressing rapidly on the previously announced TF1 engine test facility in the United Kingdom where the first ground-based demonstration of its revolutionary SABRE air-breathing rocket engine will take place. The Colorado test facility, named TF2, consists of a test building and a control room located on the east side of the Front Range Airport. The hot air for the testing will be provided by a modified afterburning jet engine configured to produce a wide range of flowrates and temperatures.

We are tremendously excited that Reaction Engines is locating their new engine test facility here at Front Range Airport and, as the future site of Spaceport Colorado, the linkages between high-speed aviation uses and the commercial space applications for this new technology are a perfect fit, said Dave Ruppel, Front Range Airport Director. Reaction Engines has been outstanding to work with and we are looking forward to being a small part of their ongoing success.

Colorado has a long history as a leader in the U.S. aerospace sector, and provides a supportive and capable location for Reaction Engines expanding U.S. activity.

Colorado is a leading aerospace state known for our innovative businesses that propel our growing aerospace economy, remarked Jay Lindell, representing the Colorado Office of Economic Development and International Trade. We are proud to have Reaction Engines in Colorado at the Front Range Airport and look forward to supporting their test operations that will lead to future cutting-edge propulsion technology.

Once TF2 achieves full operations, and following the completion of HTX testing, the company plans to make the facility available to industry, technology developers, and universities who could benefit from the facilitys unique test capabilities.

Distribution Statement A:

Approved for Public Release, Distribution Unlimited