Pressure Drop and Interception Efficiency of Multifiber Filters

Abstract

ABSTRACT. The viscous flow fields around multifiber filters have been investigated in a previous paper. The results of the previous work show that the flow becomes periodic immediately after the first fiber array downstream from the entrance if the fibers are arranged uniformly along the flow direction. The characteristics of such flow fields enable the pressure drop and the particle interception efficiency of a multifiber filter to be represented by single-fiber models. The total filtration efficiency, however, cannot be so represented since fibers interact during filtration processes. In this study, the pressure drop and the interception efficiency were investigated by making use of the viscous flow fields modeled in the previous research. The fiber separation ratio was found to have significant effects on pressure drop and efficiency.At a given volume fraction, changes in the fiber separation ratio will result in changes to the patterns of fluid flow and aerosol particle motion. Therefore, the fiber separation ratio significantly affects pressure drop and interception efficiency.

Investigation of the characteristics of particulate flows through fibrous filters using the lattice Boltzmann method

“…Liu and Wang (1997) found that Kuwabara's relation (Eq. (13)) predicts the pressure drop factor more accurately if the horizontal and vertical distances between cylinders (fibers) are considered to be equal.…”

“…In this cell model, two-dimensional geometries of the fibrous filters are simplified by placing perfectly clean fibers in square or hexagonal arrangements, perpendicular to the flow direction. One of the limitations of the cell model (Kirsch, 2007;Liu & Wang, 1997) is that it is only applicable to Brownian particles. Therefore, efforts have been made to model fibrous media as an array of fibers with inline or staggered (ordered) arrangement (Chen, Cheung, Chan, & Zhu, 2002;Kirsch, 2007;Liu & Wang, 1996Przekop, Moskal, & Gradon, 2003;Rao & Faghri, 1988), which can be used to filter particles having higher inertia.…”

“…Owing to the effect of the fiber arrangement on the pressure drop and capture efficiency (Liu & Wang, 1997), more studies on modeling the geometry of fibrous media are needed, especially studies on the random arrangement, which more closely resembles the real arrangement of fibers. In recent years, fibrous filters have been simulated in a series of works, mostly using Fluent software.…”

Simulating and Modeling Particulate Removal Processes by Elliptical Fibers

“…By the use of the cell model, Kuwabara (1959) and Happel (1959) independently derived an analytical solution of the flow field (viscous Stokes flow around a circle) and attained the theoretical formula of drag force on single cylindrical fibers oriented perpendicular to the air flow. Starting from a good description of these idealized flow fields, many researchers (Stechkina and Fuchs 1966;Fuchs 1967, 1968;Stechkina et al 1969;Lee and Liu 1982;Liu and Wang 1997) proposed analytical expressions for the pressure drop and diffusion/interception/impaction-dominated capture efficiency. Along with the development of new instruments for direct measurement of fibrous filter efficiencies, systematic experimental data are available (Lee and Liu 1981;Kasper et al 2010).…”

Interception efficiency in two-dimensional flow past confined porous cylinders

“…Viscous flow past porous bodies is of importance in various fields of science and technology including many applications of chemical engineering (Neale et al, 1973;Sutherland and Tan, 1970), specifically in porous reactors (Drott et al, 1999), filtration, and sedimentation (Liu and Wang, 1997;Vanni, 2000), as well as in biomedical research where microfluidic systems are being developed for cell separation (Chen et al, 2012) or DNA purification (Chen et al, 2007). In such applications, fluid from a microchannel must permeate into a porous collecting element which is designed to serve as a highly sensitive detector for biomarkers.…”