High-speed cinematographic recording and numerical simulation of particles depositing on electret fibres

Baumgartner, Hanspeter; Piesch, C.; Umhauer, Heinz

doi:10.1016/0021-8502(93)90073-i

Cited by 6 publications

(8 citation statements)

References 13 publications

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“…By trial calculations, the value of total fiber charge r is determined to be 460 lAs/m 2 so that the two set of results match well in the straight-line portion, where dielectrophoretic effect dominates. The chosen value is of the same order of magnitude as those obtained or used by other investigators: 775 lAs/m 2 in Brown (1979), 200-500 lAs/m 2 in Lathrache and Fissan (1986), 500 lAs/m 2 in De Haan (1987), 258-957 lAs/m 2 in Baumgartner et al (1993). Therefore this value is fixed and used in simulations hereafter unless specified otherwise.…”

Section: Model Validationmentioning

confidence: 85%

“…Many investigators have carried out experiments to study the effects of different parameters on the collection efficiencies of the electret filters (Brown 1979;Baumgartner and Lo¨ffler 1986, Fjeld and Owens 1988, Baumgartner et al 1993, Romay et al 1998). In some of these studies, numerical simulated were also involved (Baumgartner and Lo¨ffler, 1986;Baumgartner et al 1993), while in the others, useful expressions were derived for evaluation of overall collection efficiency and for evaluation of single fiber efficiency due to individual capturing mechanisms such as the dielectrophoretic and electrophoretic capture mechanisms Romay et al 1998).…”

Section: Introductionmentioning

confidence: 99%

“…In some of these studies, numerical simulated were also involved (Baumgartner and Lo¨ffler, 1986;Baumgartner et al 1993), while in the others, useful expressions were derived for evaluation of overall collection efficiency and for evaluation of single fiber efficiency due to individual capturing mechanisms such as the dielectrophoretic and electrophoretic capture mechanisms Romay et al 1998). In addition, simulations for the flow field, particle trajectory and particle deposition have also been investigated by Brown (1981), Oh et al (2002), and Kanaoka et al (2001).…”

Section: Introductionmentioning

confidence: 99%

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Numerical Model for particle deposition and loading in electret filter with rectangular split-type fibers

2005

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A simulation model for electret filter made of split type fibers has been developed to study the filtration efficiency as well as the particle loading process. The filter was assumed to be composed of rectangular fibers arranged in staggered array in which the flow field, the electrostatic field and the collection mechanisms were determined by numerical simulation. Single fiber efficiencies under various filtration conditions were calculated and compared with results obtained from semi-empirical expressions derived from experimental results. Influences of particle charge, fiber charge and orientation of fiber on the collection efficiency were evaluated. Finally the particle loading process was studied using the present model. Dendrite growth of particles in equilibrium charge state was simulated. The mechanical efficiency compensation effect was studied by a series of simulations. It is found that the loading of 1.5 lm or larger particles has a significant mechanical collection compensation to the loss in electrostatic efficiency; while for 0.4 lm particles such compensation is slow and insignificant.

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Section: Model Validationmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Numerical Model for particle deposition and loading in electret filter with rectangular split-type fibers

2005

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“…Figure 3 shows an example of lines of electric field strength around a bipolarly charged fiber (Baumgartner et al 1993). Thus, the Coulombic force F C for the charged particle and the polarization force F P for neutral particle can be written as…”

Section: Model Of the Coulombic And Polarization Forcesmentioning

confidence: 98%

“…From their experimental data they derived semiempirical expressions for calculating the singlefiber collection efficiency. Baumgartner et al (1993) employed the high-speed cinematographic technique to record the particle trajectories around an isolated electret fiber. With a fluid velocity profile retrieved from the film images, they developed a model capable of analyzing the trajectories of the particles.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of an Electret Filter Composed of an Array of Staggered Parallel Rectangular Split-Type Fibers

Cao

Cheung

Yan

2004

Aerosol Science and Technology

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The flow field through a staggered array of parallel, rectangular split-type electret fibers was numerically modeled. The particle trajectory and the collection efficiency were simulated by solving the equation of particle motion, taking into account the effects of diffusion, interception, inertial impaction, and electrostatic forces. The model was validated against results calculated from semiempirical expressions. The model was applied to investigate the role of the inertial impaction and the interception mechanisms in the particle collection by an electret fiber, the particle trajectories under various filtration conditions, the effect of the aspect ratio of the rectangular fiber on the filter penetration, and the distribution of the deposited particles on the surface of the fiber. The simulated results indicate that the inertial impaction and interception mechanisms account for a major portion of neutral particles collected by an electret fiber when the Stokes number is higher than 0.5. For neutral particles, fibers with an aspect ratio of 38/10 have almost the same penetration as fibers with an aspect ratio of 10/38; while for singly charged particles, fibers with an aspect ratio of 38/10 achieve a much lower penetration when the electrophoretic collection mechanism dominates. In addition, it is predicted that a filter composed of fibers with an aspect ratio of 38/10 will result in a lower flow resistance and thus a slower clogging process when the dielectrophoretic collection mechanism dominates.

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Charge density measurement of electret filters using alpha-ray ionizing radiation

Romay

Liu

Chae

1999

Filtration & Separation

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High-speed cinematographic recording and numerical simulation of particles depositing on electret fibres

Cited by 6 publications

References 13 publications

Numerical Model for particle deposition and loading in electret filter with rectangular split-type fibers

Numerical Model for particle deposition and loading in electret filter with rectangular split-type fibers

Numerical Study of an Electret Filter Composed of an Array of Staggered Parallel Rectangular Split-Type Fibers

Charge density measurement of electret filters using alpha-ray ionizing radiation

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