On the importance of fibers' cross-sectional shape for air filters operating in the slip flow regime

Hosseini, Sana; Tafreshi, H. Vahedi

doi:10.1016/j.powtec.2011.06.025

Cited by 85 publications

(53 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There are many analytical, numerical and empirical models that have been developed for fibrous media made up of circular fibers (Tronville and Rivers, 2005;Hosseini and Tafreshi, 2011;Joubert et al, 2011;Fotovati et al, 2012;Qian et al, 2013;Zhou et al, 2013;Xu et al, 2014). Some researchers have found that fluids flowing past fiber surfaces experience a slip which could reduce the flow resistance in a microscale channel.…”

Section: Introductionmentioning

confidence: 99%

“…Some researchers have found that fluids flowing past fiber surfaces experience a slip which could reduce the flow resistance in a microscale channel. The slip phenomenon in porous media has been vastly studied in recent literatures (Zhao and Povitsky, 2009;Hosseini and Tafreshi, 2010;Chai et al, 2011;Hosseini and Tafreshi, 2011;Kirsh and Shabatin, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…In a fibrous filter, aerodynamic slip takes place when the fiber diameter is comparable to the mean free path of the gas molecules. In this case, collisions between the gas molecules and the fibers become so infrequent that the gas can no longer be treated as a continuum phase with respect to the fibers (Hosseini and Tafreshi, 2011). Moreover, the Cunningham slip factor should be considered in the model for particles with diameter near 1 µm.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Numerical Simulation and Experimental Validation for the Filtration Performance of Fibrous Air Filter Media with LB Method

Zhou

Fan

et al. 2017

Aerosol Air Qual. Res.

View full text Add to dashboard Cite

The performance of fibrous air filter media is one of the key factors to influence the indoor air quality. In order to develop low-resistance and high-efficiency media, it is necessary to obtain a realistic media model. Based on the truncated log-normal model, the D2G9 scheme of Lattice Boltzmann (LB) method was applied to predict both the resistance and the filtration efficiency of the flow through microscale porous media. The influences of the boundary conditions were investigated. The slip and no-slip boundary conditions on fiber surfaces, as well as the non-equilibrium extrapolation scheme and the periodic scheme, were included in this study. By validating the simulated results with both the experimental and empirical values, it was found that the simulated resistance with the slip boundary on fiber surface and the periodic scheme on upper/lower walls was closer to the real value. The model established in this paper and the LB method presented here provide support for further research on optimization of the fibrous air filter media.Keywords: Fibrous media; LB method; Slip boundary condition; Resistance; Efficiency. NOMENCLATURE Abbreviations BSRbounce-back/specular-reflection LB Lattice Boltzmann LBE Lattice Boltzmann equation Latin Lettersrelaxation time of particles, (s) c s lattice sound speed (= 1/√3·δ x /δ t in D2Q9 model)distribution function at position r and time t along the direction α ( , ) KnKnudsen number L filter media thickness, (m)

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Numerical Simulation and Experimental Validation for the Filtration Performance of Fibrous Air Filter Media with LB Method

Zhou

Fan

et al. 2017

Aerosol Air Qual. Res.

View full text Add to dashboard Cite

show abstract

“…However, only a few investigations have been dedicated to explore the filtration performance of filters made of noncircular fibers. Actually, synthetic fibers can be made with a variety of shape such as square, rectangular, elliptical, trilobal even "+", "T," and "O" hollow-shaped cross-section (Ushe 1993;William and Bobby 1995;Homonoff and Dugan 2001;Sanchez et al 2007;Hosseini and Tafreshi 2011).…”

Section: Introductionmentioning

confidence: 99%

“…Here, we quote the studies of Brown (1984), Fardi and Liu (1992a), Wang (1996), Ouyang and Liu (1998), and Dhaniyala (1999) for flow field and pressure drop, and Fardi and Liu (1992b) for capture efficiencies due to Brownian diffusion and interception, Zhu et al (2000) for capture efficiency due to inertial impaction, and Adamiak (1999), Cao et al (2004) and Cheung et al (2005) for the filtration performance in an electric field. Hosseini and Tafreshi (2011) investigated the effects of fibers' cross-sectional shape on the performance of a nanofiber filter (in the slip flow regime) and a microfiber filter (in the no-slip flow regime).…”

Section: Introductionmentioning

confidence: 99%

Simulating and Modeling Particulate Removal Processes by Elliptical Fibers

Wang

Zheng

2013

Aerosol Science and Technology

View full text Add to dashboard Cite

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.

show abstract

Cactus Stem Inspired Cone‐Arrayed Surfaces for Efficient Fog Collection

Yao

Yang

et al. 2014

Adv Funct Materials

155

130

View full text Add to dashboard Cite

With the increasing world population and the rapid development of the global industry, clean water is becoming scarcer and scarcer. Means of translating latent water in fog to dominant available water, i.e., fog collection, therefore becomes highly desirable. Previously, it was demonstrated that the cactus O. Microdasys has an integrated fog collection system arising from the evenly distributed clusters of spines and trichomes on the cactus stem. Here, it is reported that the intersite of the clusters on the cactus stem is densely covered with cones, which are also capable of collecting water from fog efficiently. Inspired by these cones, using a simple method combining mechanical perforating and template replica technology, polydimethylsiloxane (PDMS) cone arrays are fabricated with different arrangements and the one in hexagonal arrangement proves to be more efficient due to the more turbulent flow filed around the staggered cones and the rapid directional movement of water drops along each cone. This investigation opens up new avenue to collect water efficiently and may also provide clues to research about dust filtering and smog removal, which is attracting increasing attention worldwide.

show abstract

On the importance of fibers' cross-sectional shape for air filters operating in the slip flow regime

Cited by 85 publications

References 24 publications

Numerical Simulation and Experimental Validation for the Filtration Performance of Fibrous Air Filter Media with LB Method

Numerical Simulation and Experimental Validation for the Filtration Performance of Fibrous Air Filter Media with LB Method

Simulating and Modeling Particulate Removal Processes by Elliptical Fibers

Cactus Stem Inspired Cone‐Arrayed Surfaces for Efficient Fog Collection

Contact Info

Product

Resources

About