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NUMERICAL MODELING OF FLUIDIZED BED
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- Author / Creator
- Shi, Hongbo
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This work focuses on validation of a commercial computational fluid dynamics (CFD) software ANSYS Fluent 16.2 applied to multi-phase modeling of fluidized beds. A two-phase Eulerian-Eulerian based model is used to numerically reproduce experiments carried out by Taghipour, F. et al (Chem. Eng. Sci., 60(24), 2005, 6857-6867). The influence of the model dimension (2D & 3D), flow regimes mod- els (laminar & turbulent), model parameters (specularity coefficient responsible for particle-wall interaction and restitution coefficient characterizing particle-particle interaction) and computational grids were investigated. The Syamlal-O’Brien and Gidaspow gas-solid drag submodels were tested. The comparison of numerical and experiment data showed that 2D simulations overpredict experimental data. 3D simulations showed good agreement between numerical calculations and experimentally measured void fraction profiles inside the bed. Results of 2D and 3D simulations revealed that the turbulence has a minor influence on the fluidized bed structure. However, it significantly affects the gas phase velocity in the upstream region of a reactor. At the same time, it was shown that a combination of E-E model parameters such as the specularity coefficient, numerical grid resolution and discretisation scheme for convective terms can lead to a good agreement between 2D CFD simulations and experimental data. Additionally, the influence of heterogeneous reactions has been studied between gas phase and solid phase inside a fluidized bed using E-E model. It was shown that heterogeneous chemical reactions have significant impact on the fluidization regimes due to local increase in the gas flow rate. This effect should be taken into account by design of chemical reactors with heterogeneous chemical reactions, e.g. fluidized bed combustors, boilers and gasifiers.
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- Subjects / Keywords
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- Graduation date
- Fall 2017
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- Type of Item
- Thesis
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- Degree
- Master of Science
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- License
- This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.