On the 19th of December 2024, Arash Nemati will defind his PhD entitled : "Condensation in Fractured Porous Media: Full-Field Measurements and Contribution to Numerical Modeling"
This work was initiated by Philippe Séchet (LEGI) and Matthieu Briffaut (3SR) and co-supervised by Bratislav Lukić (ESRF).
The project was funded by Tec21 in 2020 as part of the PhD grants programme.
Summary
The study of condensation in two-phase flow processes within porous media remains relatively under-explored due to the difficulty in visualising such phenomena and the complexity arising from the strong coupling between heat and mass transfer and the heterogeneity of the medium. However, condensation in porous media plays a critical role in many applications, including underground contamination remediation, the integrity of geothermal reservoirs, steam-based gas/oil recovery, the durability of concrete structures, and condensation in porous fabrics and insulation.
This study aims to provide a deeper understanding of these phenomena by conducting rapid neutron tomography during vapor injection experiments and introducing a novel numerical approach to model the process. Using the high-resolution NeXT imaging instrument at the Institut Laue-Langevin (ILL), 4D neutron tomography captured water content changes during vapor injection into Fontainebleau sandstone samples. Complementary X-ray and synchrotron tomography at the European Synchrotron Radiation Facility (ESRF) provided microstructural data, highlighting the role of fractures and matrix properties in water distribution and migration.
The study confirmed neutron imaging's reliability, revealing that condensed water accumulates in smaller pores while fractures act as vapor channels, facilitating condensation that is absorbed into the matrix via capillary action.
The experimental dataset was then used to calibrate and be compared to an original numerical model developed in OpenFOAM. This model solves heat transfer and two-phase flow equations in porous media, incorporating a phase-change mass transfer term. A parametric study revealed that higher vapor flow, lower thermal conductivity, and higher injection temperatures increase water accumulation, with fracture aperture influencing breakthrough times.
Jury
The jury will be composed of:
Stephen Hall – Professor, Lund University – Reviewer
Marc Prat – Emeritus Research Director, CNRS, University of Toulouse – Reviewer
Valérie Vidal – Research Director, CNRS, ENS Lyon – Examiner
Frédéric Donzé – Professor, Université Grenoble Alpes – Examiner
Sophie Roman – Associate Professor, Université d’Orléans – Examiner
Alessandro Tengattini – Associate Professor, Université Grenoble Alpes and ILL – Invited
Philippe Séchet – Associate Professor, Université Grenoble Alpes – Thesis Director
Matthieu Briffaut – Professor, Ecole Centrale de Lille - LaMcube – Co-director
Bratislav Lukić – Research Associate, ESRF and University of Manchester – Co-supervisor
Practical information
The defense will take place on the 19th of December 2024 at 1pm in room K118 at LEGI on the university campus.
About Arash Nemati
Arash has obtained a Master in mechanical engineering at Iran University of Science and Technology where he worked as a teaching assistant in computational fluid dynamics and in thermodynamics, and as a research assistant at the Energy, Water, and Environment Center of Teheran.
He has also obtained a Master in petroleum engineering at the University of Pau and worked as a research intern at Total Energies on a project dealing with the convective dissolution of CO2 during Carbon Storage in geological formations.