## Multiphase Flows and Complex Fluids
## Current Projects:## Theory and Modeling of Granular Matter
## Particle-Laden Multiphase FlowsCCSE and NETL researchers have developed CFD-DEM and CFD-PIC based approaches for multiphase flow modeling within MFIX-Exa, where the solid phase is represented either by soft-sphere DEM representation (high fidelity, but expensive), or a coarse-grained PIC representation (lower fidelity, but scalable). Current developments include implementing complex interparticle DEM models with adhesion that are relevant in biomanufacturing, and incorporating higher-fidelity solid-phase constitutive models within the PIC represetation for such adhesive contacts. MFIX-Exa also has capabilities to model thermal transport and chemical reactions in multiphase flows, allows for resolving complex geometries using embedded boundary methods, and provides AMR capabilities. Details about MFIX-Exa have been described in this paper and this paper. For more information, please contact Ishan Srivastava, or Aaron Lattanzi. ## Polydispersity in Multiphase Flows
The effect of particle size distribution on computational efficiency may be readily observed for the simple case of granular diffusion of a bidisperse mixture. The particles are seeded in three
layers and given an initial granular temperature. As the simulation evolves, particles begin diffusing between one another and colliding. Compared to a monodisperse simulation with the same number
of particles, the default
## Non-Newtonian Fluid MechanicsPrevious work from our group has demonstrated simulations of viscoplastic fluids using a highly parallelizable structured adaptive mesh refinement method in AMReX-based code incflo. Further developments included modeling solid boundaries in viscoplastic fluids using embedded boundary methods. See more details in this paper and this paper. CCSE researchers are extending this framework by incorporating elastic effects through the implementation of elastoviscoplastic (EVP) models. The robustness of the numerical implementation will be extensively tested in various flow scenarios (such as Poiseuille and Couette flows) for a range Weissenberg and Bingham numbers. Another potential avenue for development involves implementing immersed boundary methods (IBM) to model solid particle suspensions in such complex non-Newtonian fluid matrix, which is an important precursor material for various DOE-relevant applications such as battery electrode manufacturing. For more information, please contact Ishan Srivastava. ## Data-Driven Modeling of Rheologically-Complex Microstructural FluidsCCSE researchers are engaged in developing a multiscale modeling framework that explicitly couples particle-based and continuum simulations of complex fluids via active learning, thus providing a new predictive capability for domain scientists to conduct high-fidelity modeling of these materials at practical length scales. For more information, please contact Ishan Srivastava, and Andy Nonaka. |