Numerical simulation of flow involving a fractal aggregate

Hydrodynamic properties of aggregate are different from those of impermeable particles and have not been well established, owing to their complex structural feature. Therefore, this paper focuses on the study of hydrodynamic properties of an aggregate by computational fluid dynamics method. An aggregate with self-similar structure composed of four primary spheres is constructed to account for its fractal geometry. Navier-Stokes equations are applied for the whole flow field in relation to the aggregate. Both exterior and interior flow through the aggregate could be seen clearly. Fluid collection efficiency, an indication of permeability, is also obtained. Reynolds number has complicated influence on fluid collection efficiency. Furthermore, the larger the space between four primary particles is, the larger the fluid collection efficiency. The smaller the fractal dimension is, the larger the fluid collection efficiency. These findings will enable the development of more realistic models for the flocculation and material transfer dynamics of fractal aggregate. All these results contribute to further research about mass transfer between the aggregate interior and the bulk liquid solution, as well as those researches related to irregular porous structures.