Marc Prat's research while affiliated with Institut de Mécanique des Fluides de Toulouse and other places

... The definition of the boundary conditions at the top surface is still a debated question in the drying theory [21,28,29,30]. In other words, the coupling at the surface between the transport phenomena in the porous medium and in the external air in contact with the porous medium surface is not yet sufficiently well understood and modelled. ...

... In conjunction, two-phase flow simulations at the pore scale have also been carried out extensively (Zhao et al. 2019) with the aim of reproducing both microscopic and macroscopic observations. These have been performed using various representations of porous structures like pore networks (Gjennestad, Winkler & Hansen 2020;Maalal et al. 2021), X-ray or scanning-electron-microscopy-based images (Aljasmi & Sahimi 2021;Shams et al. 2021). Computations have been carried out in many different configurations using lattice-Boltzmann (Taghilou & Rahimian 2014;Shi & Tang 2018;Gu, Liu & Wu 2021) and other techniques, either based on two-fluid systems taking explicitly into account the interfaces with a volume of fluid method or continuous two-fluid approaches using level-set (Ambekar, Mondal & Buwa 2021;Jettestuen, Friis & Helland 2021) or Cahn-Hilliard models (Yang & Kim 2021) with improved algorithms making use of machine learning (see, for instance, Silva et al. (2021)). ...

... Such an opposite dependence of evaporation rate in the RFP on the contact angle is related to the Kelvin effect. The Kelvin effect refers to the change in vapour pressure above a curved interface by the following expression (Maalal, Prat & Lasseux 2021): ...

... Generating a pore network and simulating a flow in it is often cheaper, in terms of computational resources, when compared to direct numerical simulation. However, more complex transfer mechanisms, such as imbibition and drainage, are still in the study phase, and some extensive work on computational optimization has yet to be conducted, specifically on non-user-generated porous media (Maalal et al., 2021). ...

... The study of evaporation phenomena in porous media (soil, mining waste) is a long-standing research line (Fisher, 1928;Pearce et al., 1949;Rodríguez et al., 2007;Nachshon et al., 2011;Desarnaud et al., 2015;Ahmad et al., 2021). In particular, formation study of efflorescence salt crust (ESC) in porous media (soils, sands) has been the subject of several studies (Fisher, 1928;Pearce et al., 1949;Gowing et al., 2006). ...

... For such a problem, the extraction of detailed information at the pore scale is challenging even with the most advanced imaging techniques. Pore-scale investigation is essential since it not only helps to elucidate the underlying mechanisms of behaviour at the macroscale, but also provides guidelines for constructing macroscopic models using various upscaling techniques, such as the homogenization technique (Whitaker 1977), the volume averaging method (Ahmad et al. 2020) and thermodynamically constrained averaging theory (Jackson, Miller & Gray 2009). Besides, statistical information from pore-scale data can be used to validate the upscaled models (Lasseux & Valdés-Parada 2022). ...

... This compression causes a poorer water evacuation in those areas and consequently a loss of reactivity and efficiency of the MEA and the fuel cell. This has been shown using modelling and experimental studies at the microscale [33][34][35][36][37] . However, the large FoV of the neutron CT provides a comprehensive overview of the water management of the whole MEA area where previous X-ray studies had limited oversight, focusing only on one or two rib/channel interfaces. ...

... It has a clear physical concept, which assumes that the characteristic length of the periodic unit cell is fixed, while the macroscopic characteristic length approaches infinity. 9 Using the method of volume averaging, Lasseux and Vald es-Parada established upscaled equations with effective transport coefficients for a wide range of subsurface flows including inertial single-phase flow, 16 creeping flow in the slip regime, 17 gas slip flow in a fracture, 18 and single-phase flow in the matrix and pore space. 19 Wood 20 employed the method of volume averaging to obtain coarse-grained models for complex subsurface hydrologic systems whose degrees of freedom are further reduced by introducing several scaling laws. ...

... [18][19][20] Grounded in the concept of microfluidics, the microscale fluid behavior can be experimentally observed in a transparent artificial porous model (microfluidic device). [21][22][23][24][25][26] Recent advances in micro-fabrication techniques enable such studies, by accurately mimicking the porous microstructures in a microfluidic device. [27][28][29][30][31] Conventional photolithography approaches are usually applied to fabricate porous microfluidic devices. ...

... Finally, it should be noted that the situation in a fuel cell can be more complicated than considered in this paper owing to the coupling with the electrical transport, at least in the wet case. As discussed in (Belgacem et al. 2018), the current density over the GDL-CL interface can vary spatially. According to (Belgacem et al. 2018), this leads to a lower local current below the rib in the condensation regime compared to the region below the channel. ...