EMMS mixture model with size distribution for two-fluid simulation of riser flows--颗粒学报PARTICUOLOGY

Ullah, A., Jamil, I., Hamid, A., & Hong, K. (2018). EMMS mixture model with size distribution for two-fluid simulation of riser flows. Particuology, 38, 165-173. https://doi.org/10.1016/j.partic.2017.06.007

EMMS mixture model with size distribution for two-fluid simulation of riser flows

Atta Ullah^a^*, Iqra Jamil ^a, Adnan Hamid ^a, Kun Hong ^b *

a Department of Chemical Engineering, Pakistan Institute of Engineering and Applied Sciences, Islamabad 45650, Pakistan
b Jiangsu Provincial Engineering Laboratory for Biomass Conversion and Process Integration, Jiangsu Provincial Engineering Laboratory for Advanced Materials of Salt Chemical Industry, Huaiyin Institute of Technology, Huaian 223003, China

10.1016/j.partic.2017.06.007

Volume 38, June 2018, Pages 165-173

Received 24 February 2017, Revised 17 April 2017, Accepted 18 June 2017, Available online 20 October 2017, Version of Record 2 April 2018.

E-mail: atta@pieas.edu.pk; khong@hyit.edu.cn

Highlights

• EMMS mixture model was reformulated to incorporate effects of bubble/cluster size distributions.

• The model was capable of predicting axial and radial profiles in CFB risers.

• The predicted outlet fluxes were in qualitative agreement with experimental data.

Abstract

Further development of an energy-minimization multiscale modeling approach to simulating two-phase flow under turbulent conditions that considers the size distribution of mesoscale structures, i.e. bubbles and clusters, is presented. User-defined values of minimum and maximum cluster or bubble diameters were specified. A uniform size distribution was first considered as a test case, in which the drag force comprised contributions from each size group. The mathematical form of the objective function describing the energy for suspension and transport was not altered. The heterogeneity index of this new drag modification was then used to simulate pilot-scale circulating fluidized-bed risers involving Geldart group A particles. The results were validated against available experimental data. The model is capable of capturing both axial and radial profiles of flow-field variables.

Graphical abstract

Keywords

Mesoscale; Bubble; Cluster; EMMS; CFD; Riser

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