Development of Advanced Porous Media Models for High-Temperature Gas-Cooled Reactors

High-Temperature Gas-Cooled Reactors (HTGRs) are one of the major Generation IV reactor designs, offering enhanced safety features, high thermal efficiency, and strong potential for industrial heat applications. The UK government’s Advanced Modular Reactor (AMR) programme has recently identified HTGRs as the preferred design for future advanced nuclear deployment in the UK, with an aim to deliver a demonstration reactor by the early 2030s.

One prominent HTGR configuration is the pebble-bed reactor, in which spherical fuel elements (pebbles) are densely packed within the core, creating a complex and heterogeneous thermal-fluid environment. Accurately predicting flow and heat transfer in these systems is critical for safety, performance, and design assessments, yet direct high-fidelity simulations, such as Large Eddy Simulation (LES) or Direct Numerical Simulation will remain computationally prohibitive for at least several decades. Instead, porous media approximations provide a practical alternative by treating the pebble bed as an effective continuum, replacing the explicit representation of individual pebbles with averaged flow properties that account for bulk flow resistance, heat transfer, and turbulence. While this significantly reduces computational cost and enables large-scale reactor simulations, current porous approaches, based on Reynolds-averaged Navier-Stokes models, rely on empirical correlations and assumptions that may not fully capture the high-temperature, complex thermal-fluid interactions within the pebble-bed.

This PhD project will focus on advancing porous media models for pebble-bed HTGRs by leveraging newly generated high-fidelity LES datasets. These datasets, produced under a parallel investigation, will provide detailed flow and temperature information for a geometry representative of a pebble-bed HTGR core. Building upon existing expertise in porous media modelling within the Thermo-Fluids Research Group (UoM), the project will analyse and volume-average these data to develop targeted refinements or propose alternative models where existing methods prove inadequate.

Eligibility

Applicants should have, or expect to achieve, at least a 2.1 honours degree or a master’s (or international equivalent) in a relevant science or engineering related discipline. This project is suitable for Engineering or Physics graduates with a strong background in fluid mechanics and heat transfer, preferably with experience in computational modelling. It will involve the use of open-source computational fluid dynamics codes, with turbulence modelling and porous media approaches. It will also require the development of good programming skills (ideally C/C++ and Python/MATLAB or similar), good communication skills, the ability to work independently and engagement with industrial partners.

Funding

This 3.5 year PhD is fully funded, home students and students with settled status are eligible to apply. The successful candidate will receive a tax free stipend set at the UKRI rate (£19,237 for 2024/25) and tuition fees will be paid. We expect the stipend to increase each year.

Before you apply

We strongly recommend that you contact the supervisor(s) for this project before you apply. Please include details of your current level of study, academic background and any relevant experience and include a paragraph about your motivation to study this PhD project.

How to apply

Apply online through our website: https://uom.link/pgr-apply-2425. When applying, you’ll need to specify the full name of this project, the name of your supervisor, if you already have funding or if you wish to be considered for available funding through the university, details of your previous study, and names and contact details of two referees. Your application will not be processed without all of the required documents submitted at the time of application, and we cannot accept responsibility for late or missed deadlines. Incomplete applications will not be considered.

After you have applied you will be asked to upload the following supporting documents:

• Final Transcript and certificates of all awarded university level qualifications
• Interim Transcript of any university level qualifications in progress
• CV
• Supporting statement: A one or two page statement outlining your motivation to pursue postgraduate research and why you want to undertake postgraduate research at Manchester, any relevant research or work experience, the key findings of your previous research experience, and techniques and skills you’ve developed. (This is mandatory for all applicants and the application will be put on hold without it).
• Contact details for two referees (please make sure that the contact email you provide is an official university/work email address as we may need to verify the reference)
• English Language certificate (if applicable)

If you have any questions about making an application, please contact our admissions team by emailing FSE.doctoralacademy.admissions@manchester.ac.uk.

Equality, diversity and inclusion is fundamental to the success of The University of Manchester, and is at the heart of all of our activities. We know that diversity strengthens our research community, leading to enhanced research creativity, productivity and quality, and societal and economic impact. We actively encourage applicants from diverse career paths and backgrounds and from all sections of the community, regardless of age, disability, ethnicity, gender, gender expression, sexual orientation and transgender status. We also support applications from those returning from a career break or other roles.