(630b) Critical Analysis of the Foundation for Various Physical Models Used in Fluid-Particle CFD

Computational fluid dynamics (CFD) has the potential to become a promising predictive toolbox for industrial operations. Most industrial operations involve particle technology in at least one part of the process, so the benefits of accurately predicting the flow of solid particles with CFD is significant. Computational fluid (and particle) dynamic frameworks are essentially composed of software that solve the equations that govern motion, e.g., continuum-based mass, momentum, and energy balances are solved in the two-fluid method (TFM) approach to simulating fluid-particle flow. To reliably predict the particle flow, the particle-particle and fluid-particle forces must be accurately modeled. In some cases, first-principle description of these interactions is well-known. For instance, collisional stresses in TFM resulting from binary, spherical particle collisions forces are well described. Additionally, drag force on a single particle (fluid-particle interaction) can be predicted accurately with various empirical correlations. However, as will demonstrated with this work, not all particle-particle and fluid-particle interactions are well known. For example, fundamental and physical modeling approaches of particle-particle cohesion and drag on multiple particles has evaded the particle technology for decades. As a result, reliable and accurate model predictions of large-scale equipment remains elusive. Here, a critical analysis of the foundation for various physical models used in CFD is discussed. For instance, much of our understanding of cohesive particles flow is based on empirical classifications (and sometimes anecdotal experiences) of material behavior in one type of unit operation. Additionally, the physical limitations of validating the homogenous drag models that underpin the fluid-particle model predictions. In this work, a critical examination of the foundation for modeling various physical interaction is discussed as a necessary first step to developing physical models for predicting particle behavior.