“Towards a validated CFD setup for a range of fluidized beds”

Abstract

The present work aims to conduct CFD simulations of different types of fluidized beds with the same simulation setup. For this, a suitable validation experiment from literature must be identified that mimics the different states of fluidization that are of interest. The paper discusses which requirements need to be fulfilled by such a validation experiment. Different dimensionless groups need to be matched between the actual system under investigation (lab-scale gasifier) and the validation experiment from literature. This is shown using a flow regime map. The experiment is intended to provide several hydrodynamic measurements such as pressure drop, pressure drop fluctuation, voidage and velocity profiles. After a suitable reference experiment is identified from a literature review, Euler-Euler simulations are conducted to reproduce the experimental series. The applied set of models and parameters are based on the kinetic theory of granular flow. The required grid resolution and physical simulation time for averaging are carefully discussed. The numerical simulations show good agreement with the experimental results found in literature. A critical discussion about the potential limitations of the experimental setup in terms of proper gas distribution is conducted together with a discussion of the limits of the selected modeling approach. Finally, the validated simulation setup is applied to a multi-zone lab-scale gasifier. The simulation results show very good agreement with the proposed hydrodynamics in the different zones of the gasifier.