Direct simulations of particle deposition and filtration in dual-scale porous media

A two dimensional direct numerical simulation technique is developed to describe particulate flows in dual-scale porous media to predict particle deposition on the permeable porous surface in liquid composite molding processes. This individual particle level simulation accounts for hydrodynamic interaction between particles and the fluid, especially near a porous wall (fiber tow), and can predict the deposition of the particles on solid or porous surfaces. A Stokes-Brinkman coupling is employed to describe the flow in dual-scale porous media and a fictitious domain approach is used to deal with freely suspended particles in the fluid stream. A single particle deposition process is investigated extensively along with effects of the permeability of porous media, the particle size and the pressure drop. Mechanisms leading to accelerated or delayed deposition of particles are analyzed by investigating the velocity fields around the particle in close proximity of the porous surface. Finally, particle filtration simulation are performed with a large number of particles to demonstrate the feasibility of this scheme to address particle deposition and filtration during manufacturing of composites using liquid composite molding processes in which the particles are mixed with the resin and the suspension is injected into a stationary dual scale preform. (C) 2011 Elsevier Ltd. All rights reserved.