Utilizing virtual mesh to enable fully resolved CFD-DEM simulations of coarse-grained slurries comprising non-spherical particles

0579736 - ÚT 2024 PL eng A - Abstrakt
Studeník, Ondřej - Isoz, Martin
Utilizing virtual mesh to enable fully resolved CFD-DEM simulations of coarse-grained slurries comprising non-spherical particles.
15th Multiphase Workshop & Summer School. Gdaňsk, 2023. s. 10.
[Multiphase Workshop & Summer School /15./. 13.06.2023-15.06.2023, Gdaňsk]
Institucionální podpora: RVO:61388998
Klíčová slova: DEM * CFD * OpenFOAM
Obor OECD: Applied mathematics

The prevalence of suspension flows in both nature and industry promotes the development of models that can be used to accurately analyse and optimize such processes. A well-established approach providing a detailed insight into the suspension flow dynamics is the so called fully- or particle-resolved CFD-DEM simulation, which is based on using a variant of the immersed boundary method to couple the computational fluid dynamics (CFD) and discrete element method (DEM). While the fully resolved CFD-DEM allows for direct numerical simulation of particle-fluid interactions, the complexity of contact dynamics between general solid shapes often leads to approximating the shapes by spheres or by clusters of spheres, which benefits of well-defined sphere-sphere interactions. However, this approximation is inadequate for coarse-grained slurries, e.g., catalyst depositions via washcoating, where the particle shape must be considered. To enable particle-resolved CFD-DEM with truly general particle shapes, we concentrate on collisions of general particles, defined by a complex surface. The standard softDEM approach, where the contact forces are evaluated according to the overlap of the colliding pair is employed. However, the overlap length, which is the usual overlap characteristics, had to be replaced by the overlap volume.
The overlap volume evaluation for a collision of two generally shaped solids is computationally costly. This computational cost can be mitigated via our virtual mesh algorithm, an efficient and accurate tool for evaluating collision-defining parameters. The virtual mesh efficiency stems from the fact that it subdivides the space around the contact point to provide the mesh resolution required by DEM without changes to the CFD mesh itself. Furthermore, to enable simulations of particle-laden flows with a high number of collisions, e.g., flows of dense suspensions, we concentrate on the parallelization of the contact treatment, especially in the context of the domain decomposition imposed by CFD. The combination of improving the contact evaluation efficiency and contact treatment parallelization substantially increased the applicability of our in-house developed CFD-DEM solver to real-life flows.
Trvalý link: https://hdl.handle.net/11104/0349342