School of CSE Seminar Series: Min Wang

Abstract: The phase interaction models for disperse multiphase flows are crucial for modeling various scientific and engineering applications. In the existing theory of disperse multiphase flows, phase interactions are represented as forces between the phases. It is well known that models using only force-based interactions are ill-posed, resulting in non-hyperbolic governing equations. In this work, using ensemble averaging and nearest particle statistics, the fluid-particle phase interaction is decomposed into a particle-mean-field force (representing the conventional drag force) and the divergence of the particle-fluid-particle (PFP) stress. To explore the physics of PFP stress and develop a practical mathematical model, a series of particle-scale-resolved simulations have been conducted using CFD-DEM-IBM.

 

It is found that for a fluid-particle system with high particle-fluid density ratios, the PFP stress is attractive along the flow direction and repulsive in the direction perpendicular to the flow. This serves as the macroscopic representation of the well-known drafting-kissing-tumbling (DKT) phenomena observed in experiments, which is still absent in existing particle-laden flow theories. To quantify the essential physics, a preliminary PFP stress model, expressed in terms of particle volume fraction and Reynolds number, is proposed based on physical principles and particle-resolved direct numerical simulations.

 

Bio: Dr. Min Wang is a Staff Scientist in Fluid Dynamics and Solid Mechanics Group at Theoretical Division in Los Alamos National Laboratory (LANL). He obtained his PhD in computational mechanics, DEM-LBM/CFD, from Swansea University in 2016. From 10.2015-06.2018, he worked in Rockfield Software L.t.d UK as a project engineer and focused on the development of Finite Element commercial software for multi-field coupling in geomechanics. In June 2018, he moved to Los Alamos National Laboratory, first as a Postdoc Research Associate, to perform research on the multiscale theory and technique for large material deformations, and on the multiphase flow theory and related closure issues using high-resolution CFD-DEM simulations and statistical mechanics. Then he was promoted to a Staff Scientist position. Dr. Wang's research interests include computational solid and fluid mechanics; multi-material/phase flow theory; multiphysics and multiscale geomechanics, and application of machine learning to enhance the understanding of materials and multi-material/phase flows.  He has published over 60 journal articles and served as editorial roles in international journals, such as Computers and Geotechnics, Journal of Rock Mechanics and Geotechnical Engineering, Rock and Soil Mechanics and so on since 2019. His research work is primarily supported by Department of Energy, LANL and oil industries like BP.