Bubble dynamics properties of B-particles in a quasi-2D gas-solid fluidized bed: Computational particle fluid dynamics numerical simulation and post-processed by digital image analysis technique--颗粒学报PARTICUOLOGY

Yuan, Z., Huang, Z., Qin, G., Zhao, G., Ma, S., Yang, H., & Yue, G. (2024). Bubble dynamics properties of B-particles in a quasi-2D gas-solid fluidized bed: Computational particle fluid dynamics numerical simulation and post-processed by digital image analysis technique. Particuology, 86, 223-238. https://doi.org/10.1016/j.partic.2023.06.013

Bubble dynamics properties of B-particles in a quasi-2D gas-solid fluidized bed: Computational particle fluid dynamics numerical simulation and post-processed by digital image analysis technique

Zemin Yuan ^{a b}, Zhong Huang ^b, Guotao Qin ^b, Guanjia Zhao ^a, Suxia Ma ^a, Hairui Yang ^b *, Guangxi Yue ^b

a Key Laboratory of Clean and Efficient Combustion and Utilization in the Circulating Fluidized Bed, Taiyuan University of Technology, Taiyuan, 030024, China
b Department of Energy and Power Engineering, Tsinghua University, Beijing, 100084, China

10.1016/j.partic.2023.06.013

Volume 86, March 2024, Pages 223-238

Received 28 February 2023, Revised 2 June 2023, Accepted 19 June 2023, Available online 6 July 2023, Version of Record 16 July 2023.

E-mail: yhr@mail.tsinghua.edu.cn

Highlights

• CPFD scheme combining DIA is validated to be a reliable method for studying bubble dynamics in quasi-2D fluidized bed.

• Gas velocity has significant effects on bubble equivalent diameter, hold-up, bed expansion ratio, bubble rising velocity.

• Gas velocity has little influence on bubble size distribution, aspect ratio andlateral velocity for same particles.

• Two core-annular flow structures could be found in the fluidized bed.

• Proposed correlations could predict the bubble hold-up and bed expansion ratio well.

Abstract

Bubble dynamics properties play a crucial and significant role in the design and optimization of gas-solid fluidized beds. In this study, the bubble dynamics properties of four B-particles were investigated in a quasi-two-dimensional (quasi-2D) fluidized bed, including bubble equivalent diameter, bubble size distribution, average bubble density, bubble aspect ratio, bubble hold-up, bed expansion ratio, bubble radial position, and bubble velocity. The studies were performed by computational particle fluid dynamics (CPFD) numerical simulation and post-processed with digital image analysis (DIA) technique, at superficial gas velocities ranging from 2umf to 7umf. The simulated results shown that the CPFD simulation combining with DIA technique post-processing could be used as a reliable method for simulating bubble dynamics properties in quasi-2D gas-solid fluidized beds. However, it seemed not desirable for the simulation of bubble motion near the air distributor at higher superficial gas velocity from the simulated average bubble density distribution. The superficial gas velocity significantly affected the bubble equivalent diameter and evolution, while it had little influence on bubble size distribution and bubble aspect ratio distribution for the same particles. Both time-averaged bubble hold-up and bed expansion ratio increased with the increase of superficial gas velocity. Two core-annular flow structures could be found in the fluidized bed for all cases. The average bubble rising velocity increased with the increasing bubble equivalent diameter. For bubble lateral movement, the smaller bubbles might be more susceptible, and superficial gas velocity had a little influence on the absolute lateral velocity of bubbles. The simulated results presented a valuable and novel approach for studying bubble dynamics properties. The comprehensive understanding of bubble dynamics behaviors in quasi-2D gas-solid fluidized beds would provide support in the design, operation, and optimization of gas-solid fluidized bed reactors.

Graphical abstract

Keywords

Bubble dynamics properties; CPFD simulation; Quasi-2D gas-solid fluidized bed; Digital image analysis

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