Lattice Boltzmann simulation of the dispersion of aggregated Brownian particles under shear flowsT. Nishiyama1, S. Yasuda2 and T. Inamuro3
1 Department of Aeronautics and Astronautics, Kyoto University, Kyoto 606-8501, Japan
2 Department of Chemical Engineering, Kyoto University, Kyoto 615-8510, Japan
3 Department of Aeronautics and Astronautics, and Advanced Research Institute of Fluid Science and Engineering, Kyoto University, Kyoto 606-8501, Japan
The deformation and breakup processes of a particle-cluster aggregate under shear flows are investigated by the two-phase lattice Boltzmann method. In the simulation the particle is modeled by a hard droplet with large viscosity and strong surface tension. The van der Waals attraction force is taken into account for the interaction between the particles. Also, the Brownian motion is considered for nano-particles. Two important dimensionless parameters are introduced in order to classify calculated results. One is the ratio of fluid force to the maximum inter-particle force, Y, and the other is the Péclet number which is the ratio of the rate of diffusion by a shear flow to the rate of diffusion by Brownian motion. It is found that Y is the key factor in dispersion and that the Brownian motion retards the dispersion.
© EDP Sciences, Springer-Verlag 2009