par Khan, Asif
Président du jury Parente, Alessandro
Promoteur Hendrick, Patrick
Publication Non publié, 2025-11-07
Thèse de doctorat
Résumé : Porous media are widely used across diverse engineering fields—including filtration, agriculture, environmental protection, food drying, thermal insulation, space exploration, geothermal systems, and petrochemical engineering—because of their unique ability to sustain fluid flow through interconnected three-dimensional pore networks and their inherent versatility. Despite their broad utility, the accurate characterisation of the thermophysical properties of porous media remains challenging, largely due to their intricate geometries and complex manufacturing processes.This study addresses these open challenges by introducing a new and improved protocol for the manufacturing and characterisation of porous media with complex topologies. The innovative manufacturing methodology developed in the frame of this work allowed to produce homogeneous porous structures with pore sizes in the range of 2–5 μm, enabled the fabrication of complex geometries without post-processing, and contributed to cost reduction.Comparative analysis revealed that green body compacting produced porous structures with higher permeability and greater homogeneity than conventional pressing techniques.A series of dedicated experimental setups were designed and assembled to non-destructively measure key hydrodynamic properties, including porosity, capillary pressure, and permeability. These setups allowed highly accurate measurements of porosity, capillary pressure, and mass rate-of-rise, from which permeability was computed. The overall uncertainty of all measurements was within 5%. In addition, a novel concept was developed to quantify the evaporation rate of liquids from porous media using a decompression method. Both experimental data and numerical modelling confirmed the feasibility and effectiveness of this approach. To enhance the properties of porous metallic media, graphene was incorporated into the pore network through a co-sintering process. Under optimised sintering conditions, this method ensured homogeneous adhesion of graphene within the pores, improved robustness, and preserved the overall pore architecture. Moreover, graphene co-sintered samples demonstrated improved permeability in stainless steel compared to nickel and other coating-based methods.In conclusion, this work introduces a novel measurement methodology for porous media that directly links performance to internal morphological structure. The approach not only enables accurate characterisation of two-phase flow behaviour across different porous materials but also supports the re-sintering of fractured porous metallic media without compromising structural integrity or pore architecture—an advancement of relevance to space applications.

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