07 mars 2024

Webinaire Rodney O. Fox

Prof. Rodney O. Fox joined Iowa State University in 1998 as the Glenn Murphy Professor of Engineering, later becoming the Herbert L. Stiles Professor of Chemical Engineering until 2012. He is been an Associate Scientist at the US-DOE Ames Laboratory since 2001, rising to Distinguished Professor in 2010. Prof. Fox held visiting professorships in Belgium, Denmark, France, Italy, Switzerland, and The Netherlands, and was a NATO Postdoctoral Fellow in France from 1987 to 1988. Among his awards are a NSF Presidential Young Investigator Award in 1992 and ISU Outstanding Achievement in Research Award in 2007. He was elected Fellow of the American Physical Society in 2007 and the AIChE in 2020. Prof. Fox received the North American Mixing Forum Award for Excellence and Shell Particle Technology Forum Thomas Baron Award in 2016. In 2022, he was named the Fulbright-Tocqueville Distinguished Chair and Jean D’Alembert Senior Chair at the University of Paris-Saclay, CentraleSupélec. Prof. Fox’s contributions to multiphase and reactive flow modeling are groundbreaking. His group developed novel computational fluid dynamics models, including powerful quadrature-based moment methods (CQMOM, GQMOM, HyQMOM). His research spans turbulent flow, chemical reactions, and multifluid models. His books, Computational Models for Turbulent Reacting Flows (2003) and Computational Models for Polydisperse Particulate and Multiphase Systems (2013), are authoritative works in the field.
Simulation of the Grenoble bubble-column experiments

Buoyancy-driven bubbly flows exhibit complex multi-scale behavior that is difficult to capture in numerical simulations. For example, the flow in bubble columns transitions from the homogeneous to the heterogeneous regime as the superficial gas velocity increases. However, the transition point depends on several parameters such as the bubble size distribution, the sparger design, and whether bubble coalescence is present. Thus, unless the experiments are carefully designed and executed, it is difficult to use data from the literature to validate numerical simulations that are sensitive to these parameters. The Grenoble bubble- column experiments were performed under well-controlled conditions where bubble coalescence is absent and the bubble size in nearly constant. Moreover, data were taken with an optimized Doppler optical probe that simultaneously measured bubble volume fraction, bubble velocity and size, as well as the liquid velocity at a high sampling frequency. Thus, in addition the time-averaged statistics, for the first-time joint statistics such as the probability density function (pdf) of volume fraction and velocity and the related conditional velocity given volume fraction are available for validation. In this seminar, I will report on a validation study for a Eulerian two-fluid model implemented in OpenFOAM. Direct comparisons are made between the Grenoble data and the model predictions in both the homogeneous and heterogeneous regimes. Overall, the model predictions are in good agreement with the experiments, including the shape of the joint bubble-velocity, volume-fraction pdf and its dependence on the flow regime. These results are very encouraging and suggest the model can be used reliably for scale-up studies of industrial bubble columns.

07 mars 2024, 16h3017h30
Webinaire (veuillez contacter F. Romano pour obtenir le lien)

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