Kenya Kuwagi

A numerical study on agglomerate formation in a fluidized bed of fine cohesive particles

Abstract Two-dimensional (2D) DEM simulation was conducted to investigate the mechanism of agglomeration in a fluidized bed of cohesive fine particles. For the present simulation, granules were numerically generated from Geldart group C particles starting from initial agglomerates of an intermediate size. Particle pressure and agglomerate sizes were measured numerically. The behavior of agglomerates around a bubble were tracked in detail. Breakage of agglomerates above a bubble as assumed in the development of the Iwadate and Horio (Powder Technol. 100 (1998a) 223) model (I–H model) was numerically confirmed. Spots of high in-bed compression force, where agglomerate growth is supposed to take place, was clearly observed in the wake region below each bubble. Numerical results for agglomerate sizes compared fairly well with those predicted by the I–H model redeveloped for 2D cases to validate its mechanistic picture for agglomerate size determination.

Numerical Experiment of Thermoset Particles in Surface Modification System with Discrete Element Method (Quantization of Cohesive Force Between Particles by Agglomerates Analysis)

Numerical simulations using the discrete element method with similar particle assembly model are performed for the surface modification process of thermoset particles. In the simulations, the cohesive force between particles and the effect of thermophoresis are examined numerically in a particle dispersion system. Simulations are also carried out for different gas dispersion velocities. By varying the dimensionless parameter associated with the cohesive force, average agglomerate diameter increases as the cohesive force between particles increases. To the end, it is demonstrated that the cohesive force between particles can be quantitatively determined if the average agglomerate diameter is experimentally or numerically obtained.