Wurster fluidised-bed coating: Coarse-graining technique within CFD-DEM in conjunction with heat and mass transfer
Artikel i vetenskaplig tidskrift, 2024

In this study, we use a combined CFD-Discrete Element Method to assess predictive capabilities and numerical implications of a coarse-graining technique in Wurster fluidised-bed coaters. We investigated both hydrodynamics and heat and mass transfer and conducted simulations of a full three-phase system for the original and three coarse-grained systems, analysing velocity distributions, macroscopic solid stresses, moisture content and phase temperatures. We achieved a logarithmic simulation speed-up by aggregating up to 64 original particles into each coarse grain. This was accomplished while maintaining fidelity to the original CFD-DEM system in terms of reproducing with high accuracy macroscopic granular flow properties in different regions of a coater (drying, tube and bed regions). By integrating a liquid spray and humid air, we demonstrated that the phase temperatures were accurately predicted within the coarse-grained system, with a high capability of delivering liquid spray distributions with the same uniformity and drying. We also give arguments for choosing a certain degree of coarse-graining as a compromise between a desired reduction of computational costs and a trustworthy reproduction of granular-flow physics encountered in different regions of a Wurster bed. Our findings pave the way to using CFD-DEM to industrially-scaled Wurster-bed systems, which is currently unfeasible due to prohibitive computational costs.

Three-phase system


Liquid spray modelling

Coarse-graining technique

Granular flow regime characterisation

Wurster fluidised-bed coater


Philip Kjaer Jepsen

Chalmers, Mekanik och maritima vetenskaper

Chalmers, Rymd-, geo- och miljövetenskap, Energiteknik

Luis Martin De Juan

AstraZeneca AB

Astrid Boje

AstraZeneca AB

Sohan Sarangi

AstraZeneca AB

Christian von Corswant

AstraZeneca AB

Srdjan Sasic

Chalmers, Mekanik och maritima vetenskaper, Strömningslära

Powder Technology

0032-5910 (ISSN) 1873-328X (eISSN)

Vol. 443 119901







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