Rolls-Royce, in collaboration with EasyJet, has achieved a groundbreaking milestone in the development of hydrogen combustion engine technology for aviation. This achievement marks a significant step towards enabling hydrogen as a sustainable aviation fuel. Working closely with Loughborough’s National Centre for Combustion and Aerothermal Technology (NCCAT) and the German Aerospace Centre Deutsches Zentrum für Luft-und Raumfahrt (DLR), Rolls-Royce has demonstrated critical engine technology that can potentially power a range of aircraft.
The pivotal test involved a full annular combustor of a Pearl 700 engine at DLR in Cologne, which was powered entirely by hydrogen. This test successfully showcased that hydrogen can be combusted under conditions simulating maximum take-off thrust.
A key factor in this achievement was the successful design of advanced fuel spray nozzles, essential for controlling the combustion process. Hydrogen presents unique challenges as it burns at significantly higher temperatures and faster rates than traditional kerosene. The newly developed nozzles incorporated an innovative system that progressively mixes air with hydrogen to effectively manage the fuel’s reactivity. Rolls-Royce is pleased to report that the combustor’s operability and emissions were in line with expectations.
The individual nozzles underwent initial testing at intermediate pressure at Loughborough’s recently upgraded NCCAT test facilities and at DLR Cologne. Subsequently, the final full-pressure combustor tests were conducted at DLR Cologne.
Notably, last year, EasyJet and Rolls-Royce achieved a world-first by successfully running a modern aero engine, an AE2100, using green hydrogen at Boscombe Down, UK.
With the successful combustion element of the hydrogen program now well understood, ongoing efforts are focused on developing systems for delivering hydrogen to the engine and integrating these systems seamlessly.
Grazia Vittadini, Chief Technology Officer at Rolls-Royce, commented, “This is an incredible achievement in a short space of time. Controlling the combustion process is one of the key technology challenges the industry faces in making hydrogen a real aviation fuel of the future. We have achieved that, and it makes us eager to keep moving forward. I want to thank EasyJet, Loughborough University, and DLR for their dedication and support to reach this milestone.”
Johan Lundgren, CEO of EasyJet, expressed optimism about the future of hydrogen in aviation, stating, “We believe hydrogen is the future of short-haul aviation, and the success of this test and progress being made demonstrates that this is becoming ever closer. We remain optimistic that it will play a critical role in helping us achieve the ambitious goals we set out in our net-zero roadmap.”
Professor Dan Parsons, Pro Vice-Chancellor for Research and Innovation at Loughborough University, emphasized the significance of their contributions, saying, “In conjunction with its partners, Loughborough’s National Centre for Combustion and Aerothermal Technology is delighted to have supported the landmark testing and development of advanced aerospace fuel spray nozzles utilizing hydrogen fuel. This is a major advance towards net-zero aviation.”
The technologies tested at Loughborough and DLR will be integrated into the findings from the Boscombe Down tests as Rolls-Royce and EasyJet prepare for the next phase of testing – a full gas hydrogen ground test on a Pearl engine. This will ultimately lead to a comprehensive ground test on a Pearl engine utilizing liquid hydrogen. Both EasyJet and Rolls-Royce share the ambition to take this technology from ground testing to actual flight.
Rolls-Royce’s hydrogen research project receives support through various programs, including the UK’s Aerospace Technology Institute HyEST program, Germany’s LUFO 6 WOTAN program, and the European Union’s Clean Aviation CAVENDISH program. Loughborough University is a partner in both HyEST and CAVENDISH, while DLR is a partner in WOTAN and CAVENDISH. EasyJet has provided investment to support the development of hydrogen combustion engine technology for narrow-body aircraft.
