Preliminary Design of a Centrifugal Electropump for Liquid Hydrogen-Powered Aircraft Refuelling

The aviation industry plays a vital role in the global transportation network, enabling efficient global connectivity and contributing to economic growth. However, air traffic accounts for approximately 3.5% of climate warming caused by human activity. As the number of flights is expected to rise in the coming decades, and given that aviation is among the hardest sectors to decarbonize, this share is likely to increase. In response, the industry is exploring technologies to significantly reduce its climate impact. Liquid hydrogen-powered aircraft represent a promising solution, offering the potential for zero carbon emissions and significant reductions in other pollutants. However, these aircraft involve major technological challenges and require extensive research. While cur- rent efforts focus largely on aircraft design, there is limited research on liquid hydrogen ground refuelling systems, making it a critical component still underdeveloped. The objective of this thesis is to present a preliminary design of an electrically driven centrifugal pump for liquid hydrogen ground refuelling aiming to address the existing gap in the airport liquid hydrogen distribution infrastructure. The concept discussed was developed as part of the HydroLab project at FinisTerrae S.R.L., in collaboration with other consortium members, during an internship at the company. The design process began with the definition of high-level system requirements, based on stakeholder needs, cryogenic hydrogen properties, and constraints from the testing infrastructure under development in the framework of the same project. For this rea- son, a scaled down design was created using similarity laws and a smaller pump concept was developed through a one-dimensional approach. A trade-off between the possible architectures was performed using CFTurbo software leading to the selection of the most suitable configuration. A more detailed one-dimensional design was then performed for this architecture, with particular attention to the impeller geometry. The current baseline of the refuelling pump is expected to deliver a pressure rise of 5 bar at a flow rate of 20 kg/s with a rotational speed of approximately 3000 rpm. These perfor- mance targets aim to keep aircraft turnaround times comparable to those of conventional Jet A-1 refuelling, despite the different properties of liquid hydrogen. This is particularly critical for short-range aircraft, where ground time strongly influences overall utilisation and economic efficiency. The achieved results show the complexity of designing hydrogen refuelling components that meet aviation-grade performance. Further development will address key challenges identified, such as inducer cavitation and electric motor selection. This work supports the implementation of aerospace liquid hydrogen distribution system technology in Piedmont, and paves the way for future research on airport liquid hydrogen refuelling systems.