Highlighting the work done by Reaction Engines on 3D-printing an injector plate for the STOIC rocket engine, as part of the development of the SABRE air-breathing engine for the Skylon SSTO spaceplane:-
Details of the proprietary frost-control technology behind the SABRE airbreathing rocket propulsion system SABRE were publicly revealed for the first time by the developer Reaction Engines. The SABRE engine is designed to power an aerospace vehicle from a standing start to Mach 5.5 in airbreathing mode, and then onwards to low Earth orbit in pure rocket mode. A crucial component of the engine is the precooler, a complex heat-exchanger made of miles of fine tubing, which allows oxygen to be taken for rocket combustion directly from the ambient air.
The precooler chills incoming air from over 1000C to -150C in less than 0.01 seconds, before passing the cooled air through a turbo-compressor and into the rocket combustion chamber, where it is cooled with subcooled liquid hydrogen. The critical technical hurdle has been preventing the rapid buildup of ice on the precooler as the vehicle flies through moist air.
Speaking at at the American Institute of Aeronautics and Astronautics International Space Planes and Hypersonics conference in Glasgow, Reaction Engines technical director and chief designer Richard Varvill described a system of methanol injection which functions as antifreeze. The methanol is not simply injected into the airflow, as the air temperature drops below the point where methanol itself would freeze.
To make the methanol system work, Reaction Engines has “borrowed a trick from the chemical process industry,” Varvill says. “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.” While conceding this could seem counterintuitive, Varvill says the system achieves this by catching the water-methane mix and re-injecting it farther 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.”
Reaction Engines has decided to publish 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, former chief engineer for technology and future programs at Rolls-Royce, who recently took the reins as managing director of 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.” Thomas adds that Reaction is close to “having those approved.”
The Reaction Engines team are celebrating the installation and current commissioning of a new state-of-the-art high vacuum furnace at Culham Science Centre, Oxfordshire. Representatives from the UK Space Agency, Department of BIS and the European Space Agency recently visited Reaction Engines’ new pre-cooler manufacturing centre at Culham Science Centre. This state-of-the-art facility is capable of achieving temperatures up to 1200°C and a vacuum level of less than one ten billionth of the Earth’s atmosphere (10-10atm). The bespoke furnace was designed and commissioned by Reaction Engines and produced by Consarc Engineering Ltd, based in Holytown, Scotland.
With an internal diameter of nearly 3m, and a total internal volume of 25m3, this equipment is optimised for the manufacture of the full-scale SABRE pre-cooler technology which will be built, tested and validated over the course of the SABRE Engine Demonstrator Programme. The furnace was jointly funded by Reaction Engines’ private capital, alongside European Space Agency ‘General Support Technology Programme’ (GSTP) funding.
Simon Hanks, Head of Advanced Manufacturing at Reaction Engines, commented: “The furnace represents enabling technology that is virtually unique in the UK. With its exceptionally clean processing environment and a highly responsive thermal performance, REL has the means to build world-leading heat exchanger technology. This is exemplified in the full-scale pre-coolers that are soon to be manufactured and tested. With efforts underway to demonstrate the performance of the full SABRE engine cycle on a static test bed, the pre-cooler manufacturing capability will form a critical part of that undertaking”
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.
26th January 2015: Reaction Engines Ltd announces company growth and completion of first SABRE development milestone.
This year, the Reaction Engines team are expanding in staff and activities to complete the SABRE demonstrator programme, with delivery on track for 2019. The company has relocated to larger premises on Culham Science Centre; consolidated its two manufacturing subsidiaries to a single new location in Didcot; and is recruiting across the company, ready for the design, manufacture and testing of the full SABRE engine cycle. This growth phase has also included the purchase of new, bespoke equipment which will enable Reaction Engines to manufacture its proprietary SABRE pre- coolers in-house, at full scale.
The key development activities over the first year of this programme have centred on intakes and combustion systems. This activity includes the recently completed Preliminary Requirements Review development milestone, and has been 50% funded by Reaction Engines' private capital. Matching funding has been provided by the UK Space Agency, through the European Space Agency. With the UK Government's commitment of £60m and private capital secured towards the next steps in this development phase, the Reaction Engines team are positive that a full static demonstration of the SABRE engine is achievable before the end of the decade, marking the greatest advance in propulsion since the jet engine.
Alan Bond, Managing Director and Chief Engineer at Reaction Engines Ltd, commented:
“The technology we’ve proven, and our ability to integrate it with both rockets and gas turbines to create SABRE is not just a means to a better rocket. This is the beginning of a new generation of propulsion, enabling faster, more efficient transportation both on Earth and in Space. We’re already seeing humanity gaining huge benefits from space-enabled services, and I believe that our connection with space will grow considerably in the near future; Reaction Engines are breaking down the biggest barrier, which is getting into orbit in the first place. We’re opening the gateway to the solar system.”
The IET is staging a lecture by Dr Robert Bond, Corporate Programmes Director of Reaction Engines, at Huntingdon Hall in Worcester on 16th October.
"The SKYLON Space plane, powered by revolutionary SABRE rocket engines, has the potential to transform access to Space. This lecture will explore the prospects it offers for a single-stage-to-orbit launch vehicle with aircraft-like operation and will discuss work currently underway in the UK and Europe to demonstrate the engine and vehicle technology."