Interaction of cryogenic fuel storage and distribution system for LH2 aircraft - PhD

Recent research and development activities in cryogenic fuel systems have indicated that there is a need for an integrated development approach for the airframe mounted fuel storage system and the engine mounted distribution or convey system. This is due to the inherent thermo-fluidic challenges associated with the LH2 storage system like dynamic thermal stratification due to transient thermal loads, heat inleak driven flow response, boil-off gas generation and management, sloshing behaviour, vapor-liquid interface dynamics, and mixing effects. In addition to these challenges, the storage system must always ensure that the fuel convey system is always supplied with pure liquid to ensure that the aircraft performance requirements are met. This requirement of the fuel convey system to minimize or avoid vapor ingestion is a complex engineering challenge because the fuel storage system develops temporally and spatially varying multi-phase flow features during various parts of the aircraft mission profile. Various solutions to manage these requirements have looked at the fuel storage and the convey system in isolation and have resulted in sub-optimal systems. However, an integrated approach that looks at the storage and the convey systems together could result in fuel system architecture level changes that can effectively manage all the aircraft level requirements through an optimal, robust and functional fuel system.

Therefore, this PhD aims to develop an integrated approach to developing the storage and the convey system together by developing lower order models to represent storage-convey system multi-phase thermo-fluidic issues and investigate the evolution of the fuel system properties for various scenarios. The outcome of the PhD will be the development of architectural solutions that will provide a combined solution to managing storage system multi-phase flows and for avoiding vapor ingress into the convey system.

This position is part of the CDT in Net Zero Aviation, which offers a modular, cohort-based training programme with emphasis on innovation and impact, collaborative working and learning, continuous development, active engagement with partners and stakeholders and inclusion of student-led activities. You will be part of an annual cohort and will receive training at different universities and industrial partners providing world-class facilities in a supportive, innovative, inclusive and interactive learning environment.

Based at Cranfield University, a global leader in aerospace research, the project benefits from world-class experimental facilities in hydrogen testing and expertise in materials science and hydrogen technologies. The industrial sponsor, Rolls-Royce, is committed to net zero aviation by 2050 and is pioneering hydrogen propulsion systems through their Hydrogen Demonstrator program. This partnership provides a unique industrial environment, ensuring that research outcomes directly align with future aviation applications.

The expected impact of this PhD research is that it addresses a key research gap in LH2 in civil aviation: the lack of a unified, system‑level understanding of how the storage tank and the fuel conveyance system behave together under real aircraft operating conditions. The research aims to refocus the present-day practise of isolated subsystem optimisation toward architecture‑level solutions that can meet aircraft‑level performance, safety, and operability requirements. The coupled thermo-fluidic system optimization can result in architectures that inherently minimize vapor ingestion by the co-design approach. Moreover, the development of lower order tools envisioned in this PhD will provide fast, physics-based tools that can be used in early design studies to carry out rapid architecture trades and provide insights into aircraft integration. It is expected that the study will be able to provide several novel insights into suction port placement, pressurization strategies, venting and boil off gas management and pump selection criteria. This will help in the acceleration of LH2 aircraft development by providing early-stage design tools, modelling frameworks, guidance for test campaigns and data to support certification pathways. This can also reduce development cost and risk by avoiding late-stage redesigns, avoidance of oversized safety margins and reducing expensive cryogenic testing for development. Therefore, the outcome from this PhD plays a vital role in contributing in the ‘Aviation Zero Emissions Technologies’ pathway of the CDT

While working on this exciting research project, you will be provided with;