Energy budget of cold and hot gas–solid fluidized beds through CFD-DEM simulations--颗粒学报PARTICUOLOGY

Bi, L., Jiao, Y., Liu, C., Chen, J., & Ge, W. (2024). Energy budget of cold and hot gas–solid fluidized beds through CFD-DEM simulations. Particuology, 89, 153-171. https://doi.org/10.1016/j.partic.2023.10.006

Energy budget of cold and hot gas–solid fluidized beds through CFD-DEM simulations

Lei Bi^{a b}, Yunpeng Jiao^{b c}, Chunjiang Liu^a, Jianhua Chen^b *, Wei Ge^{b c}

a School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
b State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China
c School of Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China

10.1016/j.partic.2023.10.006

Volume 89, June 2024, Pages 153-171

Received 23 May 2023, Revised 12 September 2023, Accepted 20 October 2023, Available online 31 October 2023, Version of Record 6 December 2023.

E-mail: jhchen@ipe.ac.cn

Highlights

• Perform the energy budget through CFD-DEM simulations of both cold and hot flow.

• Global energy consumption of the particle sub-system can indicate the regime transitions.

• Local energy consumption can reflect mesoscale structure evolution.

• Add heat transfer mechanisms of p-f-p and p-f-w conductions into the modified CFDEM solver.

Abstract

Direct energy budget is carried out for both cold and hot flow in gas–solid fluidization systems. First, the energy paths are proposed from thermodynamic viewpoints. Energy consumption means total power input to the specific system, and it can be decomposed into energy retention and energy dissipation. Energy retention is the variation of accumulated mechanical energy in the system, and energy dissipation is the energy converted to heat by irreversible processes. Then based on the Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) framework, different energy terms are quantified from the specific flow elements of fluid cells and particles as well as their interactions with the wall. In order to clarify the energy budget, it is important to identify which system is studied: the particle-fluid system or the particle sub-system. For the cold flow, the total energy consumption of the particle sub-system can well indicate the onset of bubbling and turbulent, while the variation of local energy consumption terms can reflect the evolution of heterogeneous structures. For the hot flow, different heat transfer mechanisms are analyzed and the solver is modified to reproduce the experimental results. The impact of the heat transfer mechanisms and heat production on energy consumption is also investigated. The proposed budget method has proven to be energy-conservative and easy to conduct, and it is hopeful to be applied to other multiphase flow systems.

Graphical abstract

Keywords

Energy budget; Gas–solid fluidization; CFD-DEM; Regime transition; Heat transfer mechanism

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