New model could help make hydrogen-powered flight safer

Research at the University of Oxford, lead by Trinity’s Dr. Daniel Long and supervised by Prof. Felix Hofmann, has developed a new model that could help engineers better assess the risk of hydrogen embrittlement in components used for hydrogen-powered aircraft.

The research, published in Physical Review Letters, addresses a long-standing challenge in predicting how hydrogen moves through metals when they are exposed to differences in temperature. This is particularly important for hydrogen-powered flight, where fuel systems are expected to operate across large temperature ranges.

Hydrogen is a promising alternative to conventional aviation fuels, but it presents significant engineering challenges. When hydrogen enters a metal, even in very small concentrations, it can alter the material’s mechanical behaviour and lead to hydrogen embrittlement, potentially damaging components and reducing their strength. Predicting where hydrogen will accumulate is therefore crucial to assessing the long-term reliability of aircraft components.

The Oxford team has developed a new mechanistic framework for understanding “thermomigration” - the movement of hydrogen through a material in response to a temperature gradient. Their work identifies an important role for an “electron-wind” effect, in which heat-carrying electrons interact with mobile hydrogen atoms and influence their movement through the metal lattice. The model has been incorporated into a numerical framework for predicting hydrogen uptake and retention in metallic components.

Prof. Felix Hofmann, who is a College Lecturer in Engineering Science at Trinity, said: “This theoretical work represents an important step forward. At the same time, we are also working towards generating new experimental measurements of thermomigration in structural metals to further validate and refine these models.”

The research was carried out in collaboration with Rolls-Royce, which is investigating hydrogen as a potential fuel for aviation, and was supported by the Rolls-Royce-led HYEST programme and the EPSRC programme grant Making Hydrogen Work in Zero Carbon Jet Engines.

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