Abstract: Immiscible mixing which induces emulsification or aeration has been a major area of academic and industrial interest for the past couple of decades. This is due to its enormous involvement in a wide range of modern applications. Therefore, a combination of innovative numerical algorithms in a single numerical framework, able to accurately handle multiphase interface motion, fluid-structure interaction and turbulence modelling, is essential for predicting any mixing flow configuration (in stirred vessels or through static mixers, for instance). All of this is implemented within a robust high-performance computing architecture which enables an in-depth understanding of previously inaccessible physics for such extreme flow systems. We consider here three types of mixing systems. First, special interest will be given to an aeration-stirred vessel type [1], which is one of the most challenging configurations as the density ratio is ∼O(103) (air-liquid). Secondly, an emulsion stirred vessel type [2], where a multitude of interfacial singularities occur simultaneously. Finally, recent progress of emulsion phenomena inside a static mixer SMX [3]. The simulation outcomes for all these examples are presented in terms of spatio-temporal evolution of the interface shape and vortical structures; the evolution of the number of drops, and their size distribution, will also be presented as a parametric function of Re.
Acknowledgements: This work is supported by the EPSRC MEMPHIS (EP/K003976/1) and PREMIERE (EP/T000414/1) Programme Grants. The authors thank P&G, BP, EPSRC, PETRONAS, and the Royal Academy of Engineering (Research Chair in Multiphase Fluid Dynamics for OKM) for funding. The contribution of S. Shin, D. Juric, and J. Chergui to the numerical methods is also gratefully acknowledged.
References:
[1] L. Kahouadji, F. Liang, J. P. Valdes, S. Shin, J. Chergui, D. Juric, R. V. Craster, and O. K. Matar. The transition to aeration in two-phase mixing in stirred vessels. Flow: Applications of Fluid Mechanics vol 2: E30 (2022).
[2] F. Liang, L. Kahouadji, J. P. Valdes, S. Shin, J. Chergui, D. Juric, and O. K. Matar. Numerical study of oil-water emulsion formation in stirred vessels: effect of impeller speed. Flow: Applications of Fluid Mechanics vol 2: E34 (2022)
[3] J. P. Valdes, L. Kahouadji, F. Liang, S. Shin, J. Chergui, D. Juric, and O. K. Matar. Direct numerical simulations of liquid-liquid dispersions in a SMX mixer under different inlet conditions. Submitted to Chem. Eng. J. (https://hal.archives-ouvertes.fr/hal-03803802/)
BIO: Lyes Kahouadji is a French-educated engineer with a strong mathematics background who graduated from the University Pierre et Marie et Curie, Paris 6 (now university Paris-Sorbone). After a PhD on the topic of stability analysis, he joined the department of ChemEng at ICL in 2015, under the guidance of Prof. Omar K. Matar, and developed interests in high-performance computing for multiphase flows, Fluid-Structure Interaction, stratified flows, adaptive mesh refinement, heat and mass transfer, phase change; interfacial flows driven by thermocapillarity or surfactant-driven effects; microfluidics, and also non-Newtonian fluids including viscoplastic materials.
Contacts: l.kahouadji@imperial.ac.uk (Twitter: @LKahouadji)