Bubble dynamics in a 3‐D gas–solid fluidized bed using ultrafast electron beam X‐ray tomography and two‐fluid model |
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| Authors: | Vikrant Verma Johan T. Padding Niels G. Deen J. A. M. Kuipers Frank Barthel Martina Bieberle Michael Wagner Uwe Hampel |
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| Affiliation: | 1. Dept. of Chemical Engineering and Chemistry, Eindhoven University of Technology, MB Eindhoven, The Netherlands;2. Institute of Fluid dynamics, Helmholtz‐Zentrum Dresden‐Rossendorf Bautzner Landstr, Dresden, Germany;3. AREVA Endowed Chair of Imaging Techniques in Energy and Process Engineering, Technische Universitaet Dresden, Dresden, Germany |
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| Abstract: | Bubble characteristics in a three‐dimension gas‐fluidized bed (FB) have been measured using noninvasive ultrafast electron beam X‐ray tomography. The measurements are compared with predictions by a two‐fluid model (TFM) based on kinetic theory of granular flow. The effect of bed material (glass, alumina, and low linear density polyethylene (LLDPE), dp ～1 mm), inlet gas velocity, and initial particle bed height on the bubble behavior is investigated in a cylindrical column of 0.1‐m diameter. The bubble rise velocity is determined by cross correlation of images from dual horizontal planes. The bubble characteristics depend highly upon the particle collisional properties. The bubble sizes obtained from experiments and simulations show good agreement. The LLDPE particles show high gas hold‐up and higher bubble rise velocity than predicted on basis of literature correlations. The bed expansion is relatively high for LLDPE particles. The X‐ray tomography and TFM results provide in‐depth understanding of bubble behavior in FBs containing different granular material types. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1632–1644, 2014 |
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| Keywords: | fluidized bed X‐ray tomography two‐fluid model bubbles |
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