Fully coupled LES-DEM of particle interaction and agglomeration in a turbulent channel flow

• Published in: Computers & chemical engineering 2015-07, Vol.78, p.24-38
• Main Authors: Afkhami, M., Hassanpour, A., Fairweather, M., Njobuenwu, D.O.
• Format: Article
• Language: English
• Subjects: Agglomeration; Channel; Channels; Computational fluid dynamics; Computer simulation; Discrete element method; Fluid flow; Large eddy simulation; Surface energy; Turbulence; Turbulent flow; Two-phase flow
• ISSN: 0098-1354; 1873-4375
• DOI: 10.1016/j.compchemeng.2015.04.003

•Turbulent structure dominates particle motion creating particle–particle interactions.•Positive relationship between particle surface energy and agglomeration observed.•Process of particle agglomeration enhanced in two separate regions in channel.•In near-wall region due to high particle concentration driven by turbophoresis.•In high turbulence regions close to walls caused by shearing effect of flow. Coupled large eddy simulation and the discrete element method are applied to study turbulent particle–laden flows, including particle dispersion and agglomeration, in a channel. The particle–particle interaction model is based on the Hertz–Mindlin approach with Johnson–Kendall–Roberts cohesion to allow the simulation of van der Waals forces in a dry air flow. The influence of different particle surface energies, and the impact of fluid turbulence, on agglomeration behaviour are investigated. The agglomeration rate is found to be strongly influenced by the particle surface energy, with a positive relationship observed between the two. Particle agglomeration is found to be enhanced in two separate regions within the channel. First, in the near-wall region due to the high particle concentration there driven by turbophoresis, and secondly in the buffer region where the high turbulence intensity enhances particle–particle interactions.