# (337i) Kinetic-Based Hyperbolic Two-Fluid Models

- Conference: AIChE Annual Meeting
- Year: 2019
- Proceeding: 2019 AIChE Annual Meeting
- Group: Catalysis and Reaction Engineering Division
- Session:
- Time:
Tuesday, November 12, 2019 - 2:30pm-2:45pm

*ad hoc*fixes have been proposed to achieve hyperbolicity and are used in commercial CFD codes, the most popular being the so-called turbulent-dispersion force. While fixing the hyperbolicity problem, the physical origin of such terms is not evident and thus they represent a mathematical fix that otherwise have only minor effects on solutions.

To improve our understanding of the origin of such terms and to provide a rational approach for physics-based hyperbolicity, we have developed a kinetic-based derivation of the two-fluid model that includes the Archimedes force starting from the Boltzmann-Enskog kinetic equation. A related approach based on the Boltzmann kinetic equation was pioneered in the 1960â€™s for modeling hard-sphere fluids with disparate masses (e.g. plasmas), but did not include the Archimedes force. In this presentation, the status of hyperbolic kinetic-based two-fluid models for monodisperse multiphase flows, valid for arbitrary material-density ratios, will be reviewed. The methodology of model validation using data from direct-numerical simulation of fluid-particle flows will be described. Possible extensions to include polydispersity and other physics and chemistry will be discussed.