Modeling of the re-entrainment of particles from powder structures

Powder structures are the subject of many theoretical and experimental investigations, because of their high potential and real technological and medical applications. There are a number of papers in which the authors describe the interactions between particles in the powder, and between particles and substrate. Significant information for formulation of the model at the mezoscale can be provided by analysis of the process in a simple, well-defined system. The resuspension of powder particles in the fluid flow was investigated theoretically and a model of the process was formulated. A computer program using the molecular dynamics and lattice Boltzmann (D2Q9 and D3Q19) methods was applied for simulation of the behavior of powder structures exposed to current fluid forces. During the process simulation the local forces of particle-particle and particle-substrate interactions were calculated at each step of the iteration. The velocity and position of powder particles were determined as a result of interactions. This procedure gives us information about the properties of each particle at any time of the process. Adhesive forces in the system, modeling the agglomeration of particles, were simulated by harmonic interaction characteristic for the spring based on its stiffness and dumping coefficients. The values of these parameters are related to the powder material properties and system conditions.