Simulating and Modeling Particulate Removal Processes by Elliptical Fibers

Abstract

A lattice Boltzmann-cellular automata (LB-CA) probabilistic model for two-phase flows was used to simulate the particle capture process of elliptical fiber. The pressure drop and capture efficiency due to various capture mechanisms (Brownian diffusion, interception, and inertial impaction) were investigated. It is found that the diffusional capture efficiency of the elliptical fiber is greater than that of the circular fiber because of its larger capture area, which is proportional to the aspect ratio. When the interception or inertial impaction is dominated, aspect ratio, orientation angle, and the ratio of particle diameter to the fiber diameter affect the capture efficiency of the elliptical fiber, which is usually higher than that of the circular fiber except that the major axis is parallel to the incoming flow. The correction factors for the pressure drop and capture efficiency of elliptical fiber from those of circular fiber were attained through the Levenberg-Marquardt algorithm, which is used to fit some well-organized LB-CA simulations. These empirical correction factors can combine the classical models for circular fiber to calculate the pressure drop and capture efficiency for elliptical fiber in a simple way. Finally, the quality factors of elliptical fibers as a function of the aspect ratio and orientation angle were investigated, which is conducive to optimization configuration of elliptical fiber in different operation conditions.

The Influence of Fiber Geometry and Orientation Angle on Filtration Performance

“…Here we quote the studies of Raynor (2002) and Kirsh (2011) for flow fields and pressure drop and Raynor (2008), Regan and Raynor (2009) and Wang et al (2012b) for diffusional and interceptive efficiencies of single elliptical fiber. Recently, Wang et al (2014) in our research group obtained a series of empirical correction factors for the pressure drop and capture efficiency of elliptical fiber from the existing formulas of circular fiber.…”

“…The outstanding advantages of the LBM, compared with general numerical methods include its simple and clear physical pictures, inherent parallelism, and high capability to address complex boundary conditions, making it particularly suitable for describing the filtration of noncircular fibers with, for example, a trilobal cross-section. In the previous work, we have used the LB-CA probabilistic model to simulate the particle filtration process of elliptical fiber (Wang et al 2014). In the current study, we use the same LB-CA model to simulate the filtration processes of four noncircular fibers with triangular, rectangular, trilobal, and quatrefoil cross-sections.…”

Simulation of flow and heat transfer around a heated stationary circular cylinder by lattice gas automata

“…Flow past a circular cylinder and in simple porous media Zhou et al [8] Lattice Boltzmann method Vortex structures and particle dispersions in flows around a circular cylinder McCarthy [53] Lattice gas automata Flow through periodic arrays of cylinders Vogeler and Wolf-Gladrow [34] Lattice gas automata Flow past obstacles Wang et al [54][55][56][57] Lattice Boltzmann-cell automata However, for the propagation process, the particle will move with energy state, as follows…”

An Early Stage of Aerosol Particle Transport in Flows Past Periodic Arrays of Clear Staggered Obstructions: A Computational Study

“…Such issues are important when considering performance with respect to determination of minimal amounts of multilayered woven-wire screens as needed for achieving desired collection efficiency. Additionally, development of techniques to manufacture fibers with different cross-sections has activated investigations of filtration by noncircular fibers (Wang and Pui 2009;Xu et al 2013;Wang et al 2014). Prompted by these considerations, in the present study a numerical model that uses parameters based on woven-wire screens (Han 2007) is proposed to investigate the effects of obstruction numbers, obstruction morphology, and obstruction-to-obstruction longitudinal spacings on an early stage of particle dispersion and particle-surface collisions.…”

“…Jafari et al (2010) used a LBM model to predict a particle-laden flow past a square prism at a Reynolds number of 200 and analyzed the effects of Brownian motion and inertial impaction on deposition efficiency of aerosol particles. Very recently, a research group has proposed a lattice Boltzmann-cellular automata (LB-CA) probabilistic model that is capable of modeling non-steady-state filtration processes during filter loading for a laminar flow over a single cylindrical fiber (Wang et al 2012), multiple cylindrical fibers , and Elliptical Fibers (Wang et al 2014) respectively.…”