Structural evolution and breakage of dense agglomerates in shear flow and Taylor-Green vortex

Author(s)
S. Chen, S. Li, X. Ruan
Publisher
Elsevier
Source
Chemical Engineering Science
Keywords
adhesion, Agglomerate, breakage, Discrete element method, Fluid stress, Microparticle
Year
2019

We perform adhesive discrete-element method (DEM) calculations to investigate the structural evolution and the breakage of dense agglomerates in a shear flow and a Taylor-Green vortex. By means of adhesive DEM, all possible modes of particle contacting interactions are resolved and the free-draining approximation is employed to calculate the hydrodynamic drag. We demonstrate that, for shear flows, dense agglomerates undergo significant restructuring before breakage. The normal force between contacting particles scales in a linear way as the shear rate increases. Based on extensive simulation results, a criterion for breakage is then proposed, which is valid across a wide range of shear stress and interparticle adhesion values. The average size of fragments at the quasi-steady state after the breakage follows a power function of a particle adhesion parameter. By defining an effective shear rate, we are able to extend the findings in simple shear flows to the breakage process in the vortex.

Keywords: Discrete element method, Adhesion, Microparticle, Agglomerate, Breakage, Fluid stress,

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