Abstract
As part of its commitment to the decarbonization of the aviation sector and the UN Race to Zero global campaign, Rolls-Royce is actively developing hydrogen combustion gas turbine engine technology capable of powering a range of aircraft from 2035 onwards. Storing, pumping, metering, and combustion of hydrogen requires innovative technologies which are undergoing integration and validation through a demonstrator project, which involves the modification of a Pearl15 gas turbine engine for ground testing with gaseous and cryogenic liquid hydrogen. The design of a gas turbine needs to satisfy conventional safety & commercial requirements such as cost, weight, aero-thermal performance, and lifespan. However, the introduction of hydrogen as the primary fuel introduces novel failure modes that are driven by materials challenges including hydrogen embrittlement, increased water vapour environmental attack and materials cryogenic performance. There is the need for development of methodologies to incorporate these materials risks into component integrity assessments to ensure safe and reliable operation of engines. This study presents the materials challenges and opportunities presented by the use of hydrogen fuel in aerospace compared with more established hydrogen industries. It also covers preliminary work to assess the susceptibility of Inconel 625 and gold nickel brazes, used in the fuel spray nozzles, to hydrogen embrittlement.