Numerical simulation of the flow characteristics around and through multiple porous particles

Particle-fluid and particle-particle interactions can be widely seen in lots of natural and industrial processes. In order to understand these interactions, two-dimensional fluid flowing around and through nine porous particles was studied in this paper based on the lattice Boltzmann method due to its simplicity. Uniform spatial distribution and random spatial distribution were considered and the effects of Reynold number (Re), Darcy number (Da), and the distance between the particles (dx and dy) on the flow characteristics were analyzed in detail. The investigated ranges of the parameters were 10 <= Re <= 40, 10(-6) <= Da <= 10(-2), D <= dx <= 4D and D <= dy <= 4D (D is the diameter of the particles). For uniform spatial distribution, it is observed that when dx(dy) increases, the interactions between the particles become weak and the fluid can flow into the spacing between the particles. Besides, the average drag coefficient (C-Dave) increases with dx(dy) increasing at Re = 20 and the increase rate gradually slows down. Furthermore, the distance change in the direction vertical to inflow direction has more obvious impact on the average drag coefficient. For example, for Re = 20 and Da = 10(-4), when dx equals D and dy increases from 2D to 3D, C-Dave increases by 5.79%; when dy equals D and dx increases from 2D to 3D, C-Dave increases by 2.61%.