| Fibrous filters have been used in the filtration of particles for a long time. However, we still do not have a complete understanding of this type of filter even today. One way to help us understand more about fibrous filters is to perform model simulations and study how particles become attached to the fibers. Most existing models are basically single-fiber models which consider only flow past a single fiber. The pressure drops and the collection efficiencies are calculated using such flow fields. Although a few models solve flow fields past many fibers, the use of the Stokes equations limits their solutions to be only approximations of real flow at very low Reynolds numbers.;In the present study, a multi-fiber model has been developed. Flow fields past arrays of parallel and staggered fibers are computed by solving the incompressible steady-state Navier-Stokes equations numerically. Particle trajectories are determined by solving the particle equation of motion. The single-fiber collection efficiency due to interception and the multi-fiber filtration efficiency due to particle inertial impaction are then calculated. The results show that the viscous flow around the fibers becomes periodic immediately after the first fiber array from a filter entrance until it reaches the last fiber array. The fiber separation ratio is found, for the first time, to have a significant effect on filter pressure drop, particle collection and filtration efficiencies. The effects of filter volume fraction, interception parameter, the Reynolds number, the Stokes number, fiber separation ratio, and fiber arrangement on filter pressure drop and filtration efficiency are also discussed. The results of this study agree well with available experimental results. |
