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Rolls-Royce announced Tuesday that it had completed an industry first through its hydrogen research project. With partner easyJet, Rolls-Royce is committed to being at the forefront of the development of hydrogen combustion engine technology that is able to power various aircraft, including those in the narrow-body market segment from the mid-2030s and on.
Through work with Loughborough University in the UK and the German Aerospace Centre Deutshes Zentrum für Luft-und Raumfahrt, Rolls-Royce has proved a critical engine technology that marks a milestone in the journey to enable hydrogen as an aviation fuel. Tests were completed on a full annular combustor of a Pearl 700 engine at DLR in Cologne, running on 100 percent hydrogen. This testing has proven that the fuel can be combusted at conditions that represent maximum takeoff thrust.
The key to this achievement has been the design of the advanced fuel spray nozzles which control the combustion process. To achieve this, numerous engineering challenges had to be overcome, as hydrogen burns hotter and quicker than kerosene. The new nozzles could control the flame position using a new system that progressively mixes air with hydrogen to manage the reactivity of the fuel. Rolls-Royce was happy to confirm that the combustor operability and emissions were in line with expectations.
"This is an outstanding success story and we are more than happy to have contributed our hydrogen testing capabilities," said Markus Fischer, Divisional Board Member Aeronautics of DLR. "It was very exciting supporting this technology journey and seeing the burner technology mature in various rigs at our Institute of Propulsion Technology. This underlines again DLR's capabilities in complex applied research and the achievement, at such a high pace, was supported by our experience in real-scale testing of ground-based gas turbines."
Individual nozzles were initially tested at intermediate pressure at Loughborough's upgraded test facilities and at DLR Cologne before the final, full-pressure combustor testing took place. Last year, easyJet and Rolls-Royce set another world's first after successfully running a modern AE2100 engine on green hydrogen at Boscome Down in the UK.
The recent testing has shown that the combustion element of the hydrogen program is well understood. Work is continuing on the systems in order to deliver fuel to the engine and integrate those systems with an engine.
The technology tested at Loughborough and DLR will now be incorporated into the knowledge gained from testing at Boscombe down as easyJet and Rolls-Royce move forward to the next stage of testing. The next step is a full gas hydrogen ground test on a Pearl engine. This next stage in testing will lead to an eventual full ground test on a Pearl engine using liquid hydrogen.
"This is an incredible achievement in a short space of time," Rolls-Royce Chief Technology Grazia Vittadini said. "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."