On the role of the colloidal forces and surfactants in the film drainage between fluid particles

The development of specific liquid-liquid extraction operations is crucial for various bio-chemical processes, such as the production of biofuels. This technique is based on the differential solute affinity between two immiscible liquid phases. To enhance solute transfer, one of the phases is usually broken down into droplets to increase the exchange surface. The modeling of these dispersed two-phase flows is challenging due to their complex phenomenology, which encompasses breakage/fragmentation of inclusions, coalescence/aggregation, and the presence of both laminar and turbulent flow regimes. The difficulty in describing these phenomena is due to the intricate flows as well as the interplay of physics at different scales, ranging from colloidal forces at the molecular level to hydrodynamic forces at the flow scale. The local scale physics, including colloidal interactions and the drainage time of the film between inclusions, governs the macroscopic behavior of the two-phase flow via the rupture/coalescence phenomena and the resulting inclusion size, which in turn drives the hydrodynamic forces. Therefore, a satisfactory modeling of the large-scale system requires the correct modeling of small scale fluid mechanics and the consideration of sub-micron scale phenomena governed by colloidal forces. The innovation of the present study lies in the utilization of a multi-layer model, available in the open-source software Basilisk, to solve the film drainage equations. This model has been demonstrated to accurately predict the film dynamics in the presence of surfactants. Additionally, a diverse range of phenomena, such as the Van der Waals force, can be considered within the model. The major technical challenges are of a theoretical nature, as the film drainage equations are intrinsically coupled to the flow outside the film through the equality of tangential stresses at the interfaces. Thus, modeling the flow outside the film, which necessitates a thorough understanding of dispersed phase flows, is crucial for successfully solving the equations.
The successful student should have strong skills in fluid mechanics, physical chemistry, and applied mathematics. A strong interest in numerical simulation would be a plu
 

• Academic supervisor    Professor, Antkowiak Arnaud d’Alembert  
• Doctoral School    SMAER lien sur le site
• IFPEN supervisor     Dr, Pierson Jean-Lou, Fluid mechanics department, jean-lou.pierson@ifpen.fr  
• PhD location        IFP Energies Nouvelles, Solaize, France
• Duration and start date    3 years, starting in fourth quarter 2023
• Employer    IFP Energies Nouvelles, Solaize, France
• Academic requirements    University Master degree  fluid mechanics
• Language requirements    Fluency in French or English, willingness to learn French 
• Other requirements     Knowledge in C might be a plus