Fragmentation and restructuring of soft-agglomerates under shear

• Published in: Journal of colloid and interface science Vol. 342; no. 2; pp. 261 - 268
• Main Authors: Eggersdorfer, M.L., Kadau, D., Herrmann, H.J., Pratsinis, S.E.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 15.02.2010; Elsevier
• Subjects: Agglomerate; Agglomerates; Asymptotic properties; Break-up; Chemistry; Colloidal state and disperse state; Company structure; Discrete element method; Effective fractal dimension; Exact sciences and technology; Fractal analysis; Fractals; Fragmentation; General and physical chemistry; Restructuring; Shear flow; Surface physical chemistry; Agglomerate; Effective fractal dimension; Discrete element method; Restructuring; Break-up; Shear flow; Shear; Force; Linear structure; Theoretical study; Experimental study; Fragment; Fragmentation; Particle; Scaling law; Relaxation; Fractal dimension; Distribution
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2009.10.062

Soft-agglomerate restructuring, break-up (or fragmentation) and relaxation are studied in a simple shear flow by a discrete element method (DEM). The agglomerates, held together by van der Waals forces, rotate in the shear flow and are stretched into nearly linear structures (fractal dimension approaches unity) until they fracture at their weakest point resulting in lognormally-shaped fragment size distributions asymptotically. Individual fragments relax in the flow towards more compact agglomerates than the parent ones. The evolution of the average number of particles per fragment is described by generalized scaling laws between shear rate, onset (time-lag) of fragmentation, asymptotic fragment mass and size consistent with experimental and theoretical studies in the literature. The initial effective fractal dimension of the agglomerates influences the final one of the fragments.