Interaction of cryogenic fuel storage and distribution system for LH2 aircraft

About the Project

The project in collaboration with Rolls-Royce focuses on improving liquid hydrogen aircraft fuel systems by developing an integrated approach to the storage and conveyance subsystems. Current systems face complex thermo fluid challenges in the tank such as thermal stratification, boil off gas, sloshing, and dynamic vapor–liquid behaviour. These issues make it difficult to ensure that only pure liquid hydrogen reaches the engine conveyance system throughout a flight. The PhD will create lower order models that capture how multi phase flow features evolve across both storage and convey systems under different operating scenarios. The outcome will be optimized fuel system architectures that better manage multi phase flows and prevent vapor ingestion in future hydrogen powered aircraft.

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.

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.

The student will develop strong expertise in cryogenic fuel system engineering and the modelling of complex multiphase thermo fluid behaviour. They will gain advanced capability in reduced order modelling and simulation, enabling rapid exploration of fuel system concepts. The PhD will build cross disciplinary problem solving skills that integrate aircraft performance, control, thermodynamics and fluid dynamics. The student will also develop safety critical design thinking, particularly in managing cryogenic hazards such as vapor ingestion and pressure control. They will strengthen their digital engineering skills by creating exploratory system integration models before detailed design. The programme will cultivate an industry relevant mindset that moves beyond traditional silos and supports whole ecosystem thinking. Finally, the student will develop strong teamwork and collaboration skills by working with other researchers and stakeholders to shape informed solutions for Net Zero aviation.

Entry requirements

Applicants should have a first or second-class UK honours degree or equivalent in a relevant discipline such as aerospace engineering, mechanical engineering, physics, or related fields. Prior experience in numerical fluid dynamics is beneficial but not essential; determination, curiosity, and a willingness to learn are key attributes we value. Applicants with alternative qualifications, industry experience, or from diverse educational and professional backgrounds are also strongly encouraged to apply. We particularly welcome candidates from underrepresented groups in STEM, mature applicants, carers, or individuals returning to academia after career breaks, offering flexible working arrangements and support tailored to individual needs.

How to apply

For further information please contact:
Name: Dr David John Rajendran
Email: d.rajendran@cranfield.ac.uk

If you are eligible to apply for this studentship, please complete the online application form.

1st Interview expected: 26 May 2026
2nd Interview expected: 4 June 2026

Applications should be submitted as soon as possible, as the interview process will begin within the application period due to high demand.

Funding Notes

Sponsored by the EPSRC Centre for Doctoral Training in Net Zero Aviation and Rolls-Royce plc., This opportunity provide a fully funded 4 year full-time PhD with £25,183.00 tax free annual stipend, and additional funding for international and national conferences, training and industrial placement.

This opportunity is currently available for applicants that have UK student fee status only.