Charged Particle Collection by an Oppositely Charged Accelerating Droplet

Wang, H. C.; Stukel, J.J.; Leong, Keng H.

doi:10.1080/02786828608959105

Cited by 16 publications

(5 citation statements)

References 11 publications

(12 reference statements)

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“…It should be noticed that the experimental results are not available for the Stokes number larger than 2. The collection efficiency measured by Schmidt (86) and Wang (60,61) was for small Coulomb numbers (<≈0.5), and although it increases after particle and droplet charging, it is still below 1. Hara et al (87) obtained the results for a constant Stokes number (a constant flow), which can be estimated to 1.8, and the Coulomb number varying in the range from 0.34 to 4, but the Reynolds number is unknown.…”

Section: Fundamental Experimentsmentioning

confidence: 96%

“…Beizaie and Tien (59) concluded that the gravity is dominant for the particles co-flowing with gravity vector. Wang et al (60,61) considered the problem of particle deposition on a collector falling in a flowing gas, but their theoretical results were restricted only to two dimensions. Additional forces due to external electric field produced by a pair of electrodes were considered by Sumiyoshitani (62), Wang (63), and Shapiro and Laufer (64).…”

Section: Collection Efficiencymentioning

confidence: 99%

See 1 more Smart Citation

Wet Electroscrubbers for State of the Art Gas Cleaning

Jaworek

Balachandran

Krupa

et al. 2006

Environ. Sci. Technol.

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Current trends observed in air pollution control technology are closely related to the development of new, more efficient hybrid systems, i.e., those, which simultaneously utilize two or more physical mechanisms for dust or gaseous contaminants removal. These systems can operate more economically than conventional devices, especially in the removal of PM2.5 particles. The electrostatic scrubber (electroscrubber), discussed in this paper, is one of such types of devices, which combines advantages of electrostatic precipitators and inertial wet scrubbers, and removes many shortcomings inherent to both of these systems operating independently. The electroscrubber is a device in which Coulomb attraction or repulsion forces between electrically charged scrubbing droplets (collector) and dust particles are utilized for the removal of particles from a gas. Unlike wet electrostatic precipitators in which particles are precipitated only on the collection electrode, in electroscrubbers, the collection of dust particles takes place in the entire precipitator chamber. Compared to inertial scrubbers, the electroscrubbers can operate at lower droplet velocities, but the collection efficiency for a single droplet can be larger than 1. The paper reviews the state-of-the-art of wet electrostatic scrubbing (electroscrubbing) technique used for gas cleaning from dust or smoke particles. Three groups of problems are discussed: (1) The fundamental problems concerning the charged dust particle deposition on a charged collector, usually a drop, with a focus on different models describing the process. (2) The experimental works of fundamental importance to our knowledge referring to the scrubbing process, which can be used for validating the theory. (3) The laboratory demonstrations and industrial tests of different constructions of electroscrubbers designed for effective gas cleaning. The electroscrubber is not designed to replace wet or dry electrostatic precipitators but can be used as a complementary device following the last stage of conventional electrostatic precipitator, which helps to remove submicron particles. It was shown in the paper that a higher collection efficiency of an electroscrubber could be obtained for higher values of Coulomb number (i.e., higher electric charges on the collector and particle), and for a Stokes number lower than5 (i.e., low particle-collector relative velocity).

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Section: Fundamental Experimentsmentioning

confidence: 96%

Section: Collection Efficiencymentioning

confidence: 99%

Wet Electroscrubbers for State of the Art Gas Cleaning

Jaworek

Balachandran

Krupa

et al. 2006

Environ. Sci. Technol.

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“…In the first stage, the motion of particles is mainly affected by gravity force, drag force and electrostatic force. Their trajectories have been observed experimentally (Sumiyoshitani et al 1984;Jaworek et al 2001) or predicted numerically (Wang et al 1986;Adamiak et al 2001;Jaworek et al 2002;Balachandran et al 2003). The interactions between particles and charged droplet surface in the second stage determine the deposition efficiency.…”

Section: Introductionmentioning

confidence: 96%

“…For opposite-polarity, charged-droplets and charged-particles WES, particles deposit onto the droplet due to electrostatic attraction forces. Many studies, including numerical simulations (Pilat et al 1974;Wang et al 1986;Jaworek et al 1997Jaworek et al , 2002Kojevnikova and Zimmels 2000;Yang et al 2003;Zhao and Zheng 2008;Carotenuto et al 2010) and experimental tests (Kraemer and Johnstone 1955;Balachandran et al 2003;Jaworek et al 2006b;Krupa et al 2013), suggest that droplet-target deposition of the particles is more effective. One important reason is that the distances of deposition from particles to droplets are much closer than to chamber walls, closer distance in turn strengthens the electrostatic attractions.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of particles deposited on a single free-fall charged droplet

Zuo

Wang

Huo

et al. 2016

Aerosol Science and Technology

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Particles deposited on a free-fall charged droplet were experimentally studied. A droplet, charged under 40% Rayleigh limit, fell through the particle chamber to capture particles by electrostatic attractions. The velocity of the droplet was smaller than 2.1 m/s. The particle-laden droplet eventually spread on a glass slide, which was further analyzed using optical microscope. It was found that the equivalent number of particles captured by the charged droplet were larger than that of uncharged ones by one order of magnitude at least. Remarkably, particles on the charged droplet agglomerated into a large cluster, which indicates that the agglomerated cluster can be actively precipitated due to the gravity force if the droplet completely evaporates. The front side of the charged droplet was the predominant region to capture the particles. However, the actual area of capture was smaller than hemispheric surface.

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“…Simulation models for predicting the collision and col lection of the particles on collectors in the presence of electrostatic fields have been available in open literature over the last few decades ( − ). These studies provided the basis for modeling the effect of electrostatic field on particle collection by a moving fluid.…”

Section: Introductionmentioning

confidence: 99%

Modeling and Measurement of Electrostatic Spray Behavior in a Rectangular Throat of Pease-Anthony Venturi Scrubber

Yang

Viswanathan

Balachandran

et al. 2003

Environ. Sci. Technol.

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This paper presents the simulation and experimental results of the distribution of droplets produced by electrostatic nozzles inside a venturi scrubber. The simulation model takes into account initial liquid momentum, hydrodynamic, gravitational and electric forces, and eddy diffusion. The velocity and concentration profile of charged droplets injected from an electrostatic nozzle in the scrubber under the combined influence of hydrodynamic and electric fields were simulated. The effects of operating parameters, such as gas velocity, diameter of the scrubbing droplets, charge-to-mass ratio, and liquid-to-gas ratio on the distribution of the water droplets within the scrubber, were also investigated. The flux distribution of scrubbing liquid in the presence of electric field is improved considerably over a conventional venturi scrubber, and the effect increases with the increase in charge-to-mass ratio. Improved flux distribution using charged droplets increases the calculated overall collection efficiency of the submicron particles. However, the effect of an electric field on the droplet distribution pattern for small drop sizes in strong hydrodynamic field conditions is negligible. Simulated results are in good agreement with the experimental data obtained in the laboratory.

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Charged Particle Collection by an Oppositely Charged Accelerating Droplet

Cited by 16 publications

References 11 publications

Wet Electroscrubbers for State of the Art Gas Cleaning

Wet Electroscrubbers for State of the Art Gas Cleaning

Characteristics of particles deposited on a single free-fall charged droplet

Modeling and Measurement of Electrostatic Spray Behavior in a Rectangular Throat of Pease-Anthony Venturi Scrubber

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