Recent progresses, challenges and proposals on SF6 emission reduction approaches

The Science of The Total Environment, Journal Year: 2023, Volume and Issue: 906, P. 167347 - 167347

Published: Sept. 28, 2023

Language: Английский

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Numerical simulation of surface charge accumulation under negative discharge of different humidities and pressures

Physics of Plasmas, Journal Year: 2025, Volume and Issue: 32(2)

Published: Feb. 1, 2025

The surface discharge phenomenon of polymers severely limits their applications in electrical and electronic devices, especially complex environments. In this study, a drift-diffusion model based on hydrodynamic approach was developed to investigate the influence humidity gas pressure negative discharge. results indicate that pattern did not change under different conditions. increased accelerated formation discharges pulse current. particular, as increased, tiny pulses occurred at tail first pulse, number increased. appearance these changed charge distribution from “ring-like” “spot-like” distribution. Meanwhile, accumulation charges significantly distorted spatial electric field suppressed electron multiplication stage subsequent discharges, thus reducing current Trichel stage. It is precisely because stronger high humidity, resulting more accumulating surface, which keeping with experimental results. measured humidities show similar distinct spot-like distribution, illustrating constant All demonstrated correctness applicability simulation. pressures exhibited some similarities case levels. As amplitude decreased, decrease density.

Language: Английский

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Dynamic study of streamer interaction with fluidized particles in a plasma fluidized-bed system

Journal of Applied Physics, Journal Year: 2025, Volume and Issue: 137(13)

Published: April 1, 2025

Exploration of the interaction dynamics between plasma and fluidized particles in a fluidized-bed holds practical importance for elucidating mechanism treatment powders. In this study, we employed 2D fluid model to investigate effects particle diameter, dielectric constant, inter-particle spacing, with primary aim simulating specific consequences variations size, material type, gas-to-powder ratio (GPR) on powder processing effect. The results indicate that diameters below 300 μm exert less impact streamer propagation, enabling complete wrapping surface (100%). However, diameter 400 induce branching, leading reduction area 46%. These observations imply critical size range 300–400 achieving effective particles. Plasma ensures comprehensive coverage low constants (εr<4), while possessing higher constant (εr>8) exhibit diminished plasma-treated (80%), meaning longer durations high materials may be required achieve comparable Furthermore, as spacing increases from 10 500 μm, undergoes an initial increment, followed by subsequent reduction. Notably, at channel displays root-like branching pattern, substantial expansion area. This indicates optimal GPR system can enhance

Language: Английский

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Particle-in-cell/Monte Carlo collision simulations on dielectric barrier discharge packed with mixed dielectrics

Acta Physica Sinica, Journal Year: 2025, Volume and Issue: 74(13), P. 0 - 0

Published: Jan. 1, 2025

Packed bed dielectric barrier discharge (PB-DBD) is extremely popular in plasma catalysis applications, which can significantly improve the selectivity and energy efficiency of catalytic processes. In order to achieve some complex chemical reactions, it necessary mix different materials practical applications. this work, based on two-dimensional particle-in-cell/Monte Carlo collision (PIC/MCC) method, evolution PB-DBD packed with two mixed dielectrics numerically simulated reveal characteristics. Due polarization columns, enhancement electric field induces streamers at bottom columns high electrical permittivity (<i>ε</i>_r). The propagate downward voids between low <i>ε</i>_r, finally transitions into volume discharges. Then, a new streamer forms near upper plate propagates along void <i>ε</i>_r. Moreover, electron density <i>ε</i>_r lower than that addition, numbers <i>e</i>, N₂⁺, O₂⁺ O₂^- present profiles versus time. All N₂⁺ increase number before 0.8 ns. After ns, electrons decreases time, while keep almost constant. During whole process, keeps increasing reason for temporal be analyzed as follows. sum deposited those lost attachment reaction greater generated by ionization reaction, resulting declining trend. Comparatively, deposition balances their generation, leading constant O₂⁺. variation averaged (<span style="text-decoration:overline"><i>n</i></span>_<i>e</i>) temperature style="text-decoration:overline"><i>T</i></span>_<i>e</i>) are also under experimental parameters. Simulation results indicate both them decrease pressure or voltage amplitude. they enlarging column radius. <span style="text-decoration:overline"><i>n</i></span>_<i>e</i> increases then N₂ content working gas, style="text-decoration:overline"><i>T</i></span>_<i>e</i> monotonically increases. variations explained With pressure, frequency average free path lead less obtained per unit time from field, decreasing style="text-decoration:overline"><i>T</i></span>_<i>e</i>. first Townsend coefficient reduction style="text-decoration:overline"><i>T</i></span>_<i>e</i>, produced Hence, pressure. Additionally, mainly determined strength. Therefore, rising amplitude Based same style="text-decoration:overline"><i>n</i></span>_<i>e</i>also Consequently, surface area more polarized charges induced inner column, inducing stronger outside. Accordingly, radius rate, analyzing thresholds O₂.

Language: Английский

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Time-resolved characteristics of a nanosecond pulsed multi-hollow needle plate packed bed dielectric barrier discharge

Plasma Science and Technology, Journal Year: 2024, Volume and Issue: 26(7), P. 075401 - 075401

Published: March 7, 2024

Abstract In this paper, self-designed multi-hollow needle electrodes are used as a high-voltage electrode in packed bed dielectric barrier discharge reactor to facilitate fast gas flow through the active area and achieve large-volume stable discharge. The dynamic characteristics of plasma, generated species, energy transfer mechanisms both positive (PD) negative (ND) investigated by using fast-exposure intensified charge coupled device (ICCD) images time-resolved optical emission spectra. experimental results show that intensity, number channels, volume obviously enhanced when multi-needle is replaced electrode. During single voltage pulse period, PD mainly develops streamer mode, which stronger current, luminous E / N compared with diffuse mode observed ND. PD, gap between beads changes from 0 250 μm, bead partial standing filamentary micro-discharge, allows plasma leave local conducive propagation surface streamers. ND, only appears diffusion-like beads, regardless whether there gap. Moreover, generation excited states attributed higher than However, radical ND PD. It not directly dominated , but resonant process metastable . Furthermore, demonstrate obvious relaxation processes electron-to-vibration vibration-to-vibration, no vibration-to-rotation observed.

Language: Английский

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Simulation on the Plasma Dynamics of a Needle-Plate Barrier Discharge Packed With a Single Dielectric Bead

IEEE Transactions on Plasma Science, Journal Year: 2024, Volume and Issue: 52(5), P. 1619 - 1630

Published: May 1, 2024

Language: Английский

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Streamer evolution in nanosecond pulsed sliding surface dielectric barrier discharge: 2D numerical modelling

Journal of Applied Physics, Journal Year: 2024, Volume and Issue: 136(20)

Published: Nov. 27, 2024

The sliding surface dielectric barrier discharge (SDBD) plasma actuator enables a large interaction region between the and incoming flow, facilitating active flow control. A 2D model of discharge, initiated within three-electrode configuration, is developed. high-voltage (HV) electrode connected to positive nanosecond pulse with an amplitude 7 kV, positive/negative DC voltage applied third electrode, 10 mm inter-electrode gap. To account for charging process, simulated sufficient duration reach steady state before initiation pulse. This study aims understand characteristics SDBD investigate effects different polarities amplitudes on charge distribution, ionization wave propagation, electric field evolution, hydrodynamic perturbations. With application negative voltage, deposited neutralizes charges at streamer head, enhancing front, which extends length up electrode. In contrast, impedes net transfer, thereby inhibiting formation discharge.

Language: Английский

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Numerical simulation study on the mechanism of plasma dissociation of carbon dioxide in atmospheric pressure packed-bed reactors

Acta Physica Sinica, Journal Year: 2024, Volume and Issue: 74(2), P. 025202 - 025202

Published: Dec. 11, 2024

The streamer propagation and electric field distribution in a two-dimensional fluid model of packed bed reactor (PBR) filled with carbon dioxide are comprehensively studied by utilizing the PASSKEy simulation platform this work. spatiotemporal evolution electron density, fields key plasma species discharge process depth. PBR layered dielectric spheres is simulated using model, indicating that inner sides first layer second not main regions for reactions such as CO₂ dissociation; instead, along path outer side sphere. In work, streamers an investigated, highlighting influence anode voltage rise polarization on local enhancement. This enhancement leads density temperature to increase, which facilitats formation filamentary microdischarges surface ionization waves. work provides detailed analysis at specific points within PBR, further investigation dynamics spatial charges, revealing negative charges concentrate surface, being significantly higher than positive charges. charge closely related path, time going by, becomes dominated space. also explores deposition spheres, discusses trend distribution. Additionally, temporal species, including ions radicals, their contributions overall characteristics. production mechanisms monoxide particles, ions, oxygen analyzed, focus correlation density. Finally, energy examined integrating electrons major ions. results indicate total value approximately 1.428 mJ/m, accounting 8.8% value.

Language: Английский

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Special Issue on “Dielectric Barrier Discharges and their Applications” in Commemoration of the 20th Anniversary of Dr. Ulrich Kogelschatz’s Work

Plasma Chemistry and Plasma Processing, Journal Year: 2023, Volume and Issue: 43(6), P. 1281 - 1285

Published: Nov. 1, 2023

Language: Английский

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