Improvement, validation and application of CFD/DEM model to dense gas–solid flow in a fluidized bed--颗粒学报PARTICUOLOGY

Alobaid, F., & Epple, B. (2013). Improvement, validation and application of CFD/DEM model to dense gas–solid flow in a fluidized bed. Particuology, 11(5), 514–526. https://doi.org/10.1016/j.partic.2012.05.008

Improvement, validation and application of CFD/DEM model to dense gas–solid flow in a fluidized bed

Falah Alobaid^*, Bernd Epple

TU Darmstadt, Energiesysteme und Energietechnik, Petersenstrasse 30, 64287 Darmstadt, Germany

10.1016/j.partic.2012.05.008

Volume 11, Issue 5, October 2013, Pages 514-526

Received 15 February 2012, Revised 23 April 2012, Accepted 1 May 2012, Available online 6 November 2012.

E-mail: falah.alobaid@est.tu-darmstadt.de

Highlights

► Offset method improves calculation accuracy of fluid–particle interaction to an order of magnitude.

► Electrostatic force leads to a significant damping of the particle-wall collisions.

► Electrostatic effect causes early stabilisation state of a quasi-2D fluidized bed.

► Precise DEM simulation requires exact properties of the heterogeneous material pairing.

Abstract

Dense gas–solid flow with solid volume fraction greater than 10% and at moderate Reynolds number is important in many industrial facilities such as fluidized beds. In this work, the Euler–Lagrange approach in combination with a deterministic collision model is applied to a laboratory-scale fluidized bed. The fluid–particle interaction is studied using a new procedure called the offset method, which results in several numbers of spatial displacements of the fluid grid. The proposed method is highly precise in determining porosity and momentum transfer, thus improving simulation accuracy. A validation study was carried out to assess the results using this in-house CFD/DEM code against 5-s operation of a Plexiglas spouted-fluidized bed, showing good qualitative correlation of solid distribution in the bed and acceptable quantitative agreement of pressure drops at different positions in the bed. In view of high computing cost, special emphasis is placed on effective program design, such as application of advanced detection algorithm for particle–particle/wall collisions, the multi-grid method and parallel calculation. In this context, the influence of increasing the processor number, up to 36, on calculation efficiency was investigated.

Graphical abstract

Keywords

Dense gas–solid flow; Computational fluid dynamics; Discrete element method; Offset method; Parallelisation

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