LEANDRO GOULART DE ARAUJO
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Artigo IPEN-doc 28420 Three-dimensional transient numerical simulation of the solid volume fraction of a fluidized bed2021 - OLIVO-ARIAS, L.P.; ARAUJO, L.G.The FLUENT solver employed in the Computational Fluid Dynamics (CFD) has been extensively developed to extend its robustness and precision for a wide range of flow regimes. For that, the FLUENT solver has a numerical method in the pressure-based solver that has traditionally been used for incompressible and slightly compressible flows. The algorithm is based on the pressure that solves the equations in a segregated or decoupled mode. This algorithm has proven to be robust and versatile and has been used cooperatively with a wide range of physical models, including multiphase flows and conjugated heat transfer. However, there are applications in which the convergence rate of the segregated algorithm is not satisfactory, generally due to the need in these coupling scenarios between the continuity and momentum equations. The objective of this article is to validate the Eulerian model to determine the volumetric fractions of the solid phase fraction. For this, we used data from the literature and the PCSIMPLE algorithm (solver) at different orders of solution of the continuity, momentum, and turbulence equations. Also, we determined its efficiency in transient systems and how it would affect the results in the hydrodynamics of a three-phase fluidized bed reactor. The results were significant, thus representing the phenomenon of interaction between the liquid-solid and solid-gas phases.Artigo IPEN-doc 28419 The influence of the initial gas distribution on the dynamics of a three-phase fluidized bed reactor2021 - OLIVO-ARIAS, L.P.; ARAUJO, L.G.The hydrodynamic evolution of a three-dimensional (3D) liquid-gas-solid fluidized bed reactor was studied using computational fluid dynamics (CFD) simulations, and the results were compared with previous experimental data. The gas-solid and liquid-solid interactions were calculated using the Euler-Euler model, incorporating the kinetic theory for the solid phase. The momentum exchange coefficients for the fluid-solid interactions were calculated using the Gidaspow drag model, and the fluid-fluid interactions by using the Schiller-Naumann model. The predicted gas volume fraction agreed to the Kumar model and showed better performance with the use of higher-order discretization. Furthermore, the Peng Robinson thermodynamic correlation was used to determine the properties of the materials under high severity conditions. The results showed a consistent distribution of the phases, it was quite uniform and there was a reasonable expansion of the bed when gas injection was established as an initial condition.