CFD simulations of gas–solid flow in an industrial-scale circulating fluidized bed furnace using subgrid-scale drag models--颗粒学报PARTICUOLOGY

Shah, S., Myöhänen, K., Kallio, S., & Hyppänen, T. (2015). CFD simulations of gas–solid flow in an industrial-scale circulating fluidized bed furnace using subgrid-scale drag models. Particuology, 18, 66–75. https://doi.org/10.1016/j.partic.2014.05.008

CFD simulations of gas–solid flow in an industrial-scale circulating fluidized bed furnace using subgrid-scale drag models

Srujal Shah^a *, Kari Myöhänen ^a, Sirpa Kallio ^b, Timo Hyppänen ^a

a Department of Energy Technology, Lappeenranta University of Technology, FI-53851 Lappeenranta, Finland
b VTT Technical Research Centre of Finland, FI-02044 VTT, Finland

10.1016/j.partic.2014.05.008

Volume 18, February 2015, Pages 66-75

Received 5 December 2013, Revised 17 April 2014, Accepted 8 May 2014, Available online 22 September 2014.

E-mail: srujal.shah@lut.fi

Highlights

• Coarse mesh simulations for large circulating fluidized bed furnace were performed.

• Macroscopic drag model provided a limit for coarse mesh closure for this study.

• Applied subgrid-scale drag models show improvement over Ergun/Wen–Yu model.

• Approximation of one particle size in wide particle size distribution is difficult.

Abstract

Mesoscale flow structures such as clusters and streamers of particles are characteristic features of gas–solid flow in fluidized beds. Numerical simulations of gas–solid flows for industrial-scale fluidized beds are often performed using the Eulerian description of phases. An accurate prediction of this type of flow structure using the Eulerian modeling approach requires a sufficiently fine mesh resolution. Because of the long computational time required when using fine meshes, simulations of industrial-sized units are usually conducted using coarse meshes, which cannot resolve the mesoscale flow structures. This leads to an overestimation of the gas–solid drag force and a false prediction of the flow field. For these cases, a correction must be formulated for the gas–solid drag. We have simulated a large-scale circulating fluidized bed furnace using different gas–solid drag models and compared the model results with measurements.

Graphical abstract

Keywords

Circulating fluidized bed; Computational fluid dynamics; Two-fluid model; Drag correlation; Modeling

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