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-Recently the importance of spouted bed technology has significantly increased in the context of drying processes as well as granulation, agglomeration or coating processes. Particulate systems concerning very fine or non spherical particles that are difficult to fluidize, often cannot be treated in conventional fluidized beds. In contrast to those fluidized beds, the spouted bed technology with its specific flow structure offers the opportunity of stable fluidization under controlled conditions. Within this work the fluid dynamics of a novel spouted bed with two adjustable gas inlets is investigated. By analysis of gas fluctuation spectra by means of a fast Fourier transformation algorithm, different operation regimes are identified and depicted graphically. Furthermore, continuum CFD-modeling of the granular solid phase motion by means of an Euler/Euler approach and comparisons with experimental obtained velocity vector fields by means of particle image velocimetry (PIV) measurements will be presented in this work.

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Since the invention of the spouted bed technology by Mathur and Gishler (1955), different kinds of apparatus design were developed and a huge number of applications in nearly all branches of industry have emerged. Modeling of spouted beds by means of modern simulation tools, like discrete particle models or continuum models, has become a precious opportunity to understand the complexity of multiphase flows in these apparatus. In this work, two-dimensional continuum simulations of a novel kind of spouted bed apparatus with adjustable gas inlets are presented. Different gas-particle drag models are used to obtain a realistic flow structure. Simulated solid phase concentrations are compared with images taken during experiments. Furthermore, simulated and measured gas phase pressure fluctuations over the entire bed are contrasted allowing more accurate comparisons between the simulated and the real hydrodynamic behaviour of the spouted bed.Depuis l'invention de la technologie du lit jaillissant par Mathur et Gishler (1955), une grande variété de systèmes aété mise au point et un nombre considérable d'applications dans presque toutes les branches de l'industrie ont vu le jour. La modélisation de lits jaillissants au moyen d'outils de simulation modernes, tels que les modèles de particules discrets ou les modèles en continu, est une excellente occasion pour comprendre la complexité desécoulements multiphasiques dans ces appareils. Dans ce travail, des simulations en continu bidimensionnelles d'une nouveau type de lit jaillissant avec des entrées de gaz ajustables sont présentées. On a testé différents modèles de traînée gaz-particules pour obtenir une structure d'écoulement réaliste. Les concentrations de phases solides simulées sont comparéesà des images prises lors des expériences. Par ailleurs, les fluctuations de pression de phase gazeuse simulées et mesurées dans la totalité du lit sont contrastées, ce qui permet des comparaisons plus précises entre le comportement hydrodynamique simulé et réel du lit jaillissant.

Modern simulation tools like discrete particle models or continuum models have been established as precious methods to gain insight into the complex processes in fluidized and spouted beds. Valuable information on parameters influencing the hydrodynamics can be obtained directly from computer simulations. Numerous researchers applied two-dimensional discrete and continuum models to simulate fluidized and spouted beds. However, only few publications deal with three-dimensional continuum simulations, and very often results of three-dimensional experiments are compared with two-dimensional results. In this work, a three-dimensional simulation by application of a continuum model is presented in a prismatic spouted bed with slit-shaped gas inlets. Comparisons with two-dimensional simulations in the same geometry (Gryczka et al. 2009, Chem. Eng. Sci., in press) are also part of this publication. The influence of the third dimension on the hydrodynamic behavior (bubble formation, bubble size, etc.) will be discussed.

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