Determination of the relevant charging parameters for the modeling of unipolar chargers

Domat, Maidá; Kruis, Frank Einar; Fernández‐Díaz, J. M.

doi:10.1016/j.jaerosci.2014.01.005

Cited by 9 publications

(9 citation statements)

References 23 publications

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“…For a PSL density of 1.05 × 10 3 kg/cm 3 , the particle masses were approximately 6.69 × 10 −18 , 6.87 × 10 −17 , 5.50 × 10 −16 , 5.50 × 10 −13 , and 8.59 × 10 −12 g, corresponding to particle diameters of 23, 50, 100, 1000, and 2500 nm. According to the model for unipolar charging of particles based on Fuchs’ birth‐and‐death theory , the mean charging per particle was measured, resulting in approximately 0.92, 1.9, 4.6, 134.8, and 876.4 electrons for particle diameters of 23, 50, 100, 1000, and 2500 nm, respectively, under the conditions that the N i t product was 3.6 × 10 14 ions/m 3 s applied with a trap voltage of 25 V and a dielectric constant of 3.0.…”

Section: Resultsmentioning

confidence: 99%

“…According to the model for unipolar charging of particles based on Fuchs' birth-and-death theory [28], the mean charging per particle was measured, resulting in approximately 0.92, 1.9, 4.6, 134.8, and 876.4 electrons for particle diameters of 23, 50, 100, 1000, and 2500 nm, respectively, under the conditions that the i t product was 3.6 × 10 14 ions/m 3 s applied with a trap voltage of 25 V and a dielectric constant of 3.0.…”

Section: F I G U R E 5 (A) Velocity; (B) Electric Potential and (C) Ementioning

confidence: 99%

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Comparative study of cylindrical and parallel‐plate electrophoretic separations for the removal of ions and sub‐23 nm particles

Yang

Liu

et al. 2017

J of Separation Science

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Cylindrical and parallel-plate electrophoretic separations for the removal of ions and sub-23 nm particles were compared in this study. First, COMSOL Multiphysics® software was utilized to simulate the ion and particle trajectories inside both electrophoretic separations. The results show that ions and sub-23 nm particles are removed simultaneously and that all particles can pass through both electrophoretic separations smoothly at a trap voltage of 25 V. The experimental results show that ion losses become smaller with increasing ion flow rates, and ion losses of the cylindrical and parallel-plate electrophoretic separations range from 56.2 to 71.6% and from 43.8 to 59.6%, respectively, at ion flow rates ranging from 1-3 L/min. For the removal of ions and sub-23 nm particles, the collection efficiency of both electrophoretic separations can reach 100%, but the parallel-plate electrophoretic separation requires a lower trap voltage. The particle loss of the parallel-plate electrophoretic separation is under approximately 10%, which is lower than that of the cylindrical electrophoretic separation. In particular, for large particles (800-2500 nm), the particle losses inside the cylindrical electrophoretic separation are approximately two times higher than those inside the parallel-plate electrophoretic separation. The parallel-plate electrophoretic separation is beneficial for the removal of ions and sub-23 nm particles.

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Section: Resultsmentioning

confidence: 99%

Section: F I G U R E 5 (A) Velocity; (B) Electric Potential and (C) Ementioning

confidence: 99%

Comparative study of cylindrical and parallel‐plate electrophoretic separations for the removal of ions and sub‐23 nm particles

Yang

Liu

et al. 2017

J of Separation Science

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“…Various reviews compare these theories (Biskos, Reavell and Collings 2005c;Chang 1981;Marquard 2007). In the transition regime (Kni ~ 1, for 10 < dp < 100 nm at NTP and often up to 300 nm), the theory of Fuchs (Bricard 1962;Fuchs 1963) is commonly used to fit experimental results (Adachi, Kousaka and Okuyama 1985;Biskos, Reavell and Collings 2005c;Büscher, Schmidt-Ott and Wiedensohler 1994;Liu, Whitby and Yu 1967;Romay, Pui and Adachi 1991) or to implement numerical models (Alonso, Alguacil and Borra 2009;Domat, Kruis and Fernandez-Diaz 2014;Shaygani, Saidi and Sani 2016). For Kni > 10 the charging theory in the continuum regime would be more adapted that accounts for a part the reported discrepancies.…”

Section: Aerosol Charge Calculation and Charging Theorymentioning

confidence: 99%

“…In the most homogeneous cases, the mean Ni•t can be estimated from independent averages of residence time t and ions concentration Ni (Marquard, Meyer and Kasper 2006). Spatial evolutions of ions density along aerosol flow (Domat, Kruis and Fernandez-Diaz 2014;) and aerosol flow velocity profile requires more complete analyses to determine the Ni•t (Alonso, Alguacil and Borra 2009;Biskos, Reavell and Collings 2005b;Büscher, Schmidt-Ott and Wiedensohler 1994).…”

Section: Introductionmentioning

confidence: 99%

Post-corona unipolar chargers with tuneable aerosol size-charge relations: Parameters affecting ion dispersion and particle trajectories for charger designs

Jidenko

Bouarouri

Gensdarmes

et al. 2020

Aerosol Science and Technology

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This paper focusses on the mean charge per particle of monodisperse submicron aerosol, charged by diffusion of unipolar ions in post-corona discharge. It aims to confirm and discuss the limits of considering a single value of Ni•t to describe aerosol charging and then to present methods to control the size-charge relation. Three aerosol chargers, with different mixings of ion and aerosol flows are investigated. Despite comparable ion sources with discharge currents of a few tens of µA, the size-charge relations differs from one charger to another due to different ion-aerosol mixing conditions and subsequent ion density along particles trajectories. Discrepancies are even more noticeable as the particle size increases. Discharge current, velocities of ion and aerosol flows and electric field control post-discharge ion density in each point of the charging volume. The control of particle trajectory in expanding unipolar ion cloud, leads to tuneable size-charge relations. Aerosol inertia and charging dynamics, that both depends on particle size, affects the Ni•t experienced by the particle and thus the final charge of the particle. Operating conditions to reach a constant mean charge for particles larger than 200 nm are reported. Conclusions provide a basis to design aerosol chargers devoted to electric mobility selection for aerosol deposition, separation or electrical measurements especially to overcome the limits of mobility-to-size data inversion due to multiple charge ambiguity using diffusion chargers.

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“…In the work of Kimoto et al (2010), they estimated the effect of electrostatic dispersion on particle losses in the charging chamber with the assumption that particles are completely mixed with unipolar ions in the charging chamber and compared the calculated results with experimental results. Furthermore, Domat et al (2014a) proposed a revised model including both diffusional and electrical losses for airborne particles and ions. The electrical loss is modeled with the inclusion of a radial electric field which is considered constant throughout the charging region, while the diffusional one is expressed by a loss factor determined from the ratio between the total volume occupied by the ions and the surface area where they are probably loss.…”

Section: (3) Charge Distribution Modelmentioning

confidence: 99%

Developments in Unipolar Charging of Airborne Particles: Theories, Simulations and Measurements

Zheng

Chang

Yang

et al. 2016

Aerosol Air Qual. Res.

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Charging of airborne particle is an important process in both scientific studies and industrial applications, of which the unipolar charging takes up the major part due to higher charging efficiency. In order to understand the charging mechanism of airborne particles, accordingly to predict the efficiency of unipolar chargers, different theoretical models have been proposed and investigated in all regimes. Numerical techniques have been also adopted by researchers to analyze the charging process of airborne particles and thus to model the unipolar chargers. On the other hand, with the advent and application of various measuring techniques, the electric charges measurement of airborne particles was made possible for researchers. In this work, we mainly present a summary of these models, numerical techniques and experimental results on unipolar charging in all regimes, as well as the recent developments in the design of unipolar chargers, trying to briefly overview the development in this research field.

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Determination of the relevant charging parameters for the modeling of unipolar chargers

Cited by 9 publications

References 23 publications

Comparative study of cylindrical and parallel‐plate electrophoretic separations for the removal of ions and sub‐23 nm particles

Comparative study of cylindrical and parallel‐plate electrophoretic separations for the removal of ions and sub‐23 nm particles

Post-corona unipolar chargers with tuneable aerosol size-charge relations: Parameters affecting ion dispersion and particle trajectories for charger designs

Developments in Unipolar Charging of Airborne Particles: Theories, Simulations and Measurements

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