CENTRALE LYON - PhD Multi-fidelity optimisation of transonic and transcritical CO2 turbomachines

Research field _____________________________________________
ECL and Laboratory presentation

Founded in 1857, École Centrale de Lyon is one of the top 10 engineering schools in France. It trains more than 3,000 students of 50 different nationalities on its campuses in Écully and Saint-Étienne (ENISE, in-house school): general engineers, specialized engineers, masters and doctoral students. With the Groupe des Écoles Centrale, it has three international locations. The training provided benefits from the excellence of the research carried out in the 6 CNRS-accredited laboratories on its campuses, the 2 international laboratories, the 6 international research networks and the 10 joint laboratories with companies. Its excellent research and high-level teaching have enabled it to establish double degree agreements with prestigious universities and advanced partnerships with numerous companies. With its focus on sobriety, energy, the environment and decarbonization, Centrale Lyon intends to respond to the problems faced by socio-economic players in the major transitions.

Research field presentation:

Description of the activities

Project Context: The REVCO2 Project - PEPR SPLEEN [1]

The intermittent nature of renewable energy sources highlights the need for diversification and optimization of energy recovery and conversion systems to ensure a stable and secure energy supply. Among potential energy sources, solar radiation, biomass combustion or gasification, geothermal heat, and industrial waste heat all play critical roles. One promising solution for harnessing these energy sources is the supercritical CO2 (sCO2) Brayton cycle, which offers high thermodynamic efficiency, compact equipment, and adaptability to a wide range of heat sources, including next-generation nuclear reactors and industrial waste heat. This PhD thesis is part of the PEPR REVCO2 project, a massive collaborative effort among four research laboratories (CETHIL, Lafset, LMFA and LUSAC) to fully develop a versatile reversible sCO2 Brayton cycle targeted to harvest industrial waste heat. In this project, LMFA Centrale Lyon focuses on global design of the turbomachinery stages.

PhD thesis Objectives and Methodology

The overarching objective of the PhD thesis research project is to combine numerical tools with multiple levels of accuracy in order to design the turbomachines (compressors and turbines) that will be used in the reversible Brayton cycle-based system aiming at the recycling of industrial waste heat. The PhD candidate will conduct his/her research on the basis of an already existing first-principles based tool (TBC-rad) that will be first extended to take into account supercritical thermodynamic effects in CO2 and complemented with a supersonic module grounded on the work of Bufi & Cinnella [2]. In a second step, using Bayesian processes [3] and new acquisition functions the candidate will combine three levels of fidelity (first-principles based tool / RANS / Lattice Boltzmann Method) to design centrifugal turbomachines answering the needs of the project REVCO2. Numerical simulations will be carried out using shared local (PMCS2I) and national (GENCI) computing resources.

Throughout the REVCO2 project, the PhD candidate will engage in exchanges with the other partners. The results obtained from the multi-fidelity design method will serve as input data for the REVCO2 consortium, in particular for the team at CETHIL which will analyze the insteady behaviour of the entire thermodynamic system.

[1] https://www.pepr-spleen.fr/en/accueil-english/
[2] Buffi, E. and Cinnella, Robust optimization of supersonic ORC nozzle guide vanes, Journal of Physics: Conference Series, 2017.
[3] Liam, D. et al. , Multifidelity Optimization using Statistical Surrogate Modeling for Non-Hierarchical Information Sources, 56th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference 2015.

Required skills / qualifications________________________________

Diplomas: Engineering or Master graduates (in September/October 2026)

Experience:

Knowledge required: Strong background in fluid mechanics and numerical flow simulation. A significant part of the work will involve scientific programming and in-depth physical analysis of flow phenomena.  The ideal candidate is passionate about shape optimization and the new opportunities offered by numerical design in turbomachinery.

Operational skills: Prior experience in CFD and/or CFD code development (e.g. Python, Fortran, C++) would be a considered as a strong asset.

Behavioural skills: team player, creative but thorough

Work context/environment

The PhD project will be jointly supervised at LMFA by Martin Buisson (CInnov Research Engineer, design and turbomachinery shape optimization specialist), Alexis Giauque (Associate Professor ECL, thermodynamics and turbo-machinery specialist) and Christophe Corre (Professor ECL, shape optimization and thermodynamics specialist)

The doctoral candidate will benefit from regular meetings to closely support the progress of the research. The successful candidate will join a stimulating research environment and become part of a growing team working on turbomachines for renewable energies.

The Laboratoire de Mécanique des Fluides et d’Acoustique (LMFA) is a major research actor in fluid mechanics and acoustics in France, and is located on the campus of École Centrale de Lyon (Écully, France) close to the city of Lyon.