Charge Electric Field Research Articles

Evolution laws of charge mobility of transformer oil and pressboard material with temperature and electric field strength

Abstract Charge mobility, a pivotal parameter in the space charge analysis model for oil-pressboard insulation of converter transformer under DC electric fields, predominantly relies on theoretical or empirical data. The prevalent omission of empirical, measurement-based evaluations, combined with the neglect of temperature and electric field intensity effects, introduces uncertainties in the calculation of electric field and charge dynamics. Grounded on the principles of the electroacoustic pulse technique for space charge measurements, our investigation established a temperature-controlled platform to determine the charge-charge mobility in oil and pressboard insulation mediums. Utilizing diverse oil-pressboard insulation systems, this study identified the temporal patterns of both positive and negative charge mobilities and unravelled the mechanisms modulated by temperature and electric field intensity: (1) with increasing temperatures (from 20 °C to 80 °C) and intensifying electric field strengths (from 5kV mm−1 to 25kV mm−1), the charge mobility within transformer oil and pressboard exhibits a rising trend. Notably, temperature variations exert the most significant influence, yielding amplifications up to 24.8 times. (2) The intrinsic properties of different transformer oils and oil-impregnated pressboards result in pronounced differences in their charge transport behaviors. Specifically, naphthenic-based oil demonstrates enhanced charge mobility relative to its paraffin-based counterpart. In contrast, transformer oils with higher kinematic viscosities exhibit diminished charge mobility compared to those with lower viscosities. (3) A linear relationship is observed between the oil absorption rate and electrical conductivity, aligning closely with the insulating pressboard’s charge mobility. The evaluation of electric field and interface charge dynamics in oil-pressboard insulation under both DC and polarity-reversed conditions revealed that the electric field decay in naphthenic-based oil is more rapid than in paraffin-based oils. Moreover, both the magnitude and rate of interface charge accumulation in naphthenic-based oils exceed those in paraffin-based variants, further validating the accuracy of our charge mobility measurements and ensuing analysis.

Competing mechanisms of charge-induced electric field distortion and charge-involved neutralization on surface discharge

Charge-induced surface discharge poses a critical risk to the operational reliability of high-voltage direct current gas-insulated equipment and pulsed power system. In this study, we investigate the effects of charge-induced electric field distortion and charge involvement during surface discharge by separately depositing charge spots on two dielectric layers. The results show that deposited positive charges inhibit positive streamer development, whereas negative charges facilitate it, primarily due to electric field distortion induced by deposited charges. Nevertheless, the involvement of deposited charges in streamer development predominantly exhibits a neutralizing effect, exerting an opposite influence on the streamers. This highlights a competitive relationship between deposited charge involvement and electric field distortion. Additionally, the neutralization of deposited charges with electron avalanches reduces the impact of charge-induced electric field distortion, thereby mitigating its effects on discharge.

Microstructure evolution of CdZnTe crystals irradiated by heavy ions

Consideration of irradiation effects is important for in-orbit operation and radiation protection in aerospace applications. The configuration of irradiation defects and their impact on deteriorating the carrier transport properties of CZT crystals need to be clarified. In this study, the microdefect evolution mechanism of CdZnTe (CZT) crystals under 10 MeV Chlorine (Cl) ion irradiation at flux of 1×1010∼1×1012 n·cm-2 are investigated. The stacking faults first appear in the CZT crystal at 4.5×10-4 displacement per atom (dpa), which are categorized into slip-type, gap-type and vacancy-type. In order to hinder the further expansion of stacking fault, S-shaped stacking fault dipole appears. When the dpa reaches 4.5×10-2, the local phase transition occurs in the damage zone to form CuPt-A ordered phase with ZnTe/CdTe periodic arrangement because the fluctuation in local composition and strain caused by cascade collisions. The deterioration of electric field distribution and charge collection caused by irradiation damage layer leads to the decrease of γ-ray detection ability. The energy resolution (ER) of the CZT detector for γ-ray can be maintained at 30.6% when the ion flux accumulates to 1×1012 n·cm-2, revealing high irradiation hardness. Consequently, these findings provide a theoretical basis for the radiation damage recovery of CZT detectors, further demonstrating that CZT crystals are the most competitive new generation of room-temperature nuclear radiation detection materials, and can provide radiation protection strategies for similar compound semiconductor materials.

Electric Field Features and Charge Behavior in Oil-Pressboard Composite Insulation under Impulse Voltage

Oil-pressboard/paper insulation materials are essential in transformers for ensuring their safe and stable operation, primarily due to their roles in spatial electric field distribution and charge migration mechanisms. Current spatial distribution analyses rely on computational methods that lack empirical validation, particularly for oil-pressboard/paper composites. This study leverages the principles of the Kerr electro-optic effect to develop a rapid measurement platform for electric fields within oil-pressboard/paper insulation under impulse voltage conditions, which measures the spatial electric field characteristics using Cu-Cu and Al-Al electrodes under various scenarios: with asymmetric and symmetric pressboard coverage and different numbers of insulating paper layers. Findings indicated: (1) In asymmetric pressboard models, Cu-Cu electrodes exhibit a consistent peak electric field of approximately 16 kV/mm, while Al-Al electrodes show peak values of 18.13 kV/mm and −14.98 kV/mm. Charge density patterns are similar, with Cu-Cu at about 68 μC/m2 and Al-Al at 11.2 μC/m2 and −124.8 μC/m2. (2) Symmetric models present consistent peak electric fields and charge densities for both polarities. (3) Increasing insulating paper layers elevates electric field strengths. Both electrodes show the similar peak field of about 17 kV/mm with differing paper layers due to higher charge injection from the Al electrode. (4) Utilizing the Schottky effect and field emission principles, the study clarifies charge generation and migration mechanisms. These insights could provide a theoretical foundation for designing and verifying oil-pressboard/paper insulation structures in transformers.

Robust Electric-Field Control of Colossal Exchange Bias in CrI3 Homotrilayer.

Controlling exchange bias (EB) by electric fields is crucial for next-generation magnetic random access memories and spintronics with ultralow energy consumption and ultrahigh speed. Multiferroic heterostructures have been traditionally used to electrically control EB and interfacial ferromagnetism through weak/indirect coupling between ferromagnetic and ferroelectric films. However, three major bottlenecks (lattice mismatch, interface defects, and weak/indirect coupling in multiferroic heterostructures) remain, resulting in only a few tens of milli-tesla EB field. Here, this study reports a robust electric-field control recipe to dynamically tailor the EB effect in a pure CrI3 homotrilayer on a ferroelectric Y-doped HfO2 (HYO) substrate, and demonstrate a colossal and tunable EB field (HE) from -0.15 to +0.33 T, giving rise to an EB modulation of 0.48 T. The charge doping due to ferroelectric HYO film divides a homo-configuration of CrI3 homotrilayer into one antiferromagnetic (AFM) bilayer CrI3 and one ferromagnetic (FM) monolayer CrI3, favoring direct exchange coupling. The synergies of charge doping and electric field induce a transition of magnetic orders from AFM to FM phase in bilayer CrI3, which is also supported by first-principles calculations, leading to the robust electric control of colossal EB effect. The results therefore open numerous opportunities for exploring 2D spintronics, memories, and braininspired in-memory computing.

Permittivity enhancement of Al2O3/ZrO2 dielectrics with the incorporation of Pt nanoparticles

Al2O3/ZrO2 (A/Z) layers with embedded Pt nanoparticles (Pt-nps) at the interface of A/Z have been used to create a dielectric film with an enhanced permittivity. The Pt-nps and dielectrics are both grown by the atomic layer deposition process, which is complementary metal–oxide–semiconductor compatible. In order to control the thickness ratio of Pt-nps in the overall dielectrics more easily, the thickness of the ZrO2 layer is changed from 12 to 30 nm with a fixed thickness of 12 nm for Al2O3 and constant growth cycles of 70 for Pt-nps. The results show that the introduction of Pt-nps is beneficial to the enhancement of the dielectric permittivity. As the thickness of ZrO2 is 30 nm, the capacitance density increases from 2.5 to 5.1 fF/μm2 with the addition of Pt-nps, i.e., a doubling of the capacitance density achieved. Additionally, the leakage current at 2 V increases from 1.1 × 10−8 to 1.5 × 10−7 A/cm2. Furthermore, the dielectric breakdown field decreases from 5.4 to 2.7 MV/cm. The electric field distribution simulation and charging–discharging test imply that interfacial polarization is built at the interface of Pt-nps and the dielectric films, which contributes to the dielectric permittivity enhancement, and local electric field increasing in the affinity of Pt-nps gives rise to the deterioration of the leakage current and breakdown electric field.

Investigation of Partial Discharge Transformation Characteristics in Polyimide (PI) Insulations under High-Frequency Electric Stress.

This research delves into the primary issue of polyimide (PI) insulation failures in high-frequency power transformers (HFPTs) by scrutinizing partial discharge development under high-frequency electrical stress. This study employs an experimental approach coupled with a plasma simulation model for a ball-sphere electrode structure. The simulation model integrates the particle transport equation, Poisson equation, and complex chemical reactions to ascertain microscopic parameters, including plasma distribution, electric field, electron density, electron temperature, surface, and space charge distribution. The effect of the voltage polarity and electrical energy on the PD process is also discussed. The contact point plays a pivotal role in triggering partial discharges and culminating in the breakdown of PI insulation. Asymmetry phenomena were found between positive and negative half-cycles by analyzing the PD data stage by stage. A significant number of PDs increased at every stage and the PD amplitude was higher during the negative cycle at the initial stage, but in later stages, the PD amplitude was found to be higher in the positive half-cycle, and scanning electron microscopy (SEM) revealed that the maximum damage occurred near the contact point junction. The simulation results show that the plasma initially accumulates the electron density near the contact point junction. Under the action of the electric field, plasma starts traveling at the PI surface outward from the contact point. Before the PD activity, all parameters have higher values in the plasma head. The microscopic parameters reveal maximum values near the contact point junction, during PD activities where significant damage takes place. These parameter distributions exhibit a decreasing trend over time as when the PD activity ends. The model's predictions are consistent with the experimental data. The paper lays the foundation for future research in polymer insulation design under high-frequency electrical stress.

Origin of the Efficiency Roll-off in Quantum Dot Light-Emitting Diodes: An Electrically Excited Transient Absorption Spectroscopy Study.

In situ characterizations of charge injection dynamics, equilibrated concentration, and electric field distributions shed light on the critical mechanisms of quantum dot light-emitting diodes (QD-LEDs). In this work, we developed electrically excited transient absorption spectroscopy, which can provide the above key information, to investigate the efficiency roll-off of QD-LEDs. We found that the average electron populations per QD are low when QD-LEDs exhibit efficiency roll-off, excluding Auger recombination as the main cause. We also revealed that the weak electrical field inside the QD layer under forward biases has a negligible impact on the efficiency. Interestingly, we found that as the voltage increases the electron concentration in the QD layer saturates at very low levels. When combined with the concomitant efficiency roll-off, we propose electron leakage is the main loss at elevated driving voltages. We further demonstrate that increasing the electron confinement potential with the ZnS shell enables us to efficiently mitigate the efficiency roll-off.

Study on the Relationship between Electron Transfer and Electrical Properties of XLPE/Modification SR under Polarity Reversal.

The insulation of high-voltage direct-current (HVDC) cables experiences a short period of voltage polarity reversal when the power flow is adjusted, leading to sever field distortion in this situation. Consequently, improving the insulation performance of the composite insulation structure in these cables has become an urgent challenge. In this paper, SiC-SR (silicone rubber) and TiO2-SR nanocomposites were chosen for fabricating HVDC cable accessories. These nanocomposites were prepared using the solution blending method, and an electro-acoustic pulse (PEA) space charge test platform was established to explore the electron transfer mechanism. The space charge characteristics and field strength distribution of a double-layer dielectric composed of cross-linked polyethylene (XLPE) and nano-composite SR at different concentrations were studied during voltage polarity reversal. Additionally, a self-built breakdown platform for flake samples was established to explore the effect of the nanoparticle doping concentration on the breakdown field strength of double-layer composite media under polarity reversal. Therefore, a correlation was established between the micro electron transfer process and the macro electrical properties of polymers (XLPE/SR). The results show that optimal concentrations of nano-SiC and TiO2 particles introduce deep traps in the SR matrix, significantly inhibiting charge accumulation and electric field distortion at the interface, thereby effectively improving the dielectric strength of the double-layer polymers (XLPE/SR).

The formation process and mechanism of coaxial electrostatic atomization of nanofluid oil film droplets

Abstract In coaxial electrostatic atomization cutting, the atomization effect of nanofluid oil film droplets directly affects the cooling and lubrication performance. To further understand the formation process of tiny oil film water droplets in coaxial electrostatic atomization, this paper takes LB2000/water, LB2000/0.1 vol.% graphite water-based nanofluids, LB2000/0.3 vol.% graphite water-based nanofluids, LB2000/0.5 vol.% graphite water-based nanofluids as the research object. Coaxial electrostatic atomization simulation is carried out based on the determined common voltage of the conical jet (-6.5 kV). The formation process of nanofluid oil film water droplets was analyzed using electric field force, charge concentration, and volume force, and the droplet states under different fluid types were compared. The results show that when nanoparticles are added to the inner fluid, the charge concentration increases, the electric field force and volume increase, and the formation speed of the cone jet increases significantly.

Collection efficiencies of cylindrical and plane parallel ionization chambers: analytical and numerical results and implications for experimentally determined correction factors

Objectives. To derive a collection efficiency formula, fGauss , for cylindrical ionization chambers in pulsed radiation beams from a volume recombination model of Boag et al (1996 Phys. Med. Biol. 41 885–97) including free electrons. To validate fGauss and a parallel plate chamber formula fexp using an ion transport code and calculate changes in collection efficiencies caused by electric field charge screening at 0.1–100 mGy doses-per-pulse. And to determine collection efficiencies CE∞ predicted at infinite voltage in the absence of avalanche effects by fitting scaled formulae to efficiencies computed for 100–400 V chamber voltages and 10 and 100 mGy doses-per-pulse. Approach. Calculations were performed for an idealized parallel plate chamber with 2 mm electrode separation d , and for an idealized cylindrical chamber with 0.5 and 2.333 mm inner and electrode radii rin and rout . Main results. fGauss and fexp predict the same collection efficiencies for cylindrical and parallel plate chambers satisfying d2=(rout2−rin2)ln(rout/rin)/2 , an equivalence condition met by the chambers studied. Without charge screening, efficiencies computed using the code equalled fGauss and fexp . With screening, efficiencies changed by ⩽0.03%, ⩽1.1% and ⩽21.3% at 1, 10 and 100 mGy doses-per-pulse, and differed between the chambers by ⩽0.9% and ⩽19.6% at ⩽10 and 100 mGy dose-per-pulse. For fits of fexp and fGauss , CE∞ values were ⩽1.2% and ⩽17.6% from unity at 10 and 100 mGy per pulse respectively, closer than for other formulae tested. Significance. Allowing for screening, fGauss and fexp described computed collection efficiencies to within 0.03%, 1.1% and 21.3% at doses-per-pulse ⩽1, 10 and 100 mGy. Equivalence of the two chambers broke down at 100 mGy per pulse. Departures of CE∞ values from unity suggest that collection efficiencies determined experimentally by fitting fGauss or fexp to readings made at multiple voltages will be accurate to within 1.2% and 17.6% at 10 and 100 mGy per pulse respectively.

Exploring the Impact of Steric Effects on Ion Removal of Water Solutions under the Influence of an Electric Field

In this study, we examine the movement of ions that are in a water solution which flows along a duct, due to the existence of an electric field, taking into account the size of the ions, a phenomenon known as the steric effect. We compare the results from the above model with the classical one (the one that uses the Boltzmann distribution where ions are considered dimensionless) for various parameters such as surface charge density, electric field and differential capacitance. It is shown that for dilute water solutions (1019–1024 ions/m3 final concentration at the center of the duct), with ions of valence z=1 (let us say saline water), steric effects become important for potentials greater than 1 V, and the phenomenon is more pronounced at higher concentrations. Furthermore, the steric effect model is applied to the calculation of the percentage of reduction in ion concentration in the main volume of the solution as a function of duct width for various electrode potentials and initial ion concentrations. Removal times are also calculated using Modified PNP equations which take into account steric effects. It is found that with a potential of 2.6 V, a 96% reduction in ions is achieved in the main volume of the solution for duct width 0.1 mm for 1021 ions/m3 final concentration at the center of the duct within approximately 1.6 s, while the percentage drops to 80% for duct width 1 mm. For smaller potentials, no noticeable decrease in concentration is observed, while for higher potentials, there are more impressive results, but we must be very careful because there is the case of other electrochemical phenomena taking place. The results are better when reducing the width of the duct, but relatively large widths are considered for the method to be practically applicable. With the increase in the concentration of the ions, their reduction percentage in the main volume of the solution decreases but remains significant up to 1023 ions/m3 final concentration at the center of the duct. In addition, the completion time is shown to be proportional to the duct width. Therefore, for example, with the other parameters the same (2.6 V, 1021 ions/m3) but with L~1 mm, the completion time can be estimated to be approximately 16 s. This observation enables us to estimate the completion time for different duct widths, eliminating the need for repeated numerical computation of the MPNP equations.

Weak acid hydrolysis strategy to oxygen vacancy enriched BiOBrnI1-n nanosheet for photodegrading various contaminants

BiOBrnI1-n solid solution enriched with oxygen vacancies (OVs) was obtained using simple hydrolysis method and exhibited excellent ability to remove various contaminants, inclusive of bisphenol A (BPA), rhodamine B (RhB), methyl orange (MO), tetracycline hydrochloride (TCH) and sulfamethazine (SMT). The photocatalytic degradation efficiency of optimal BiOBrnI1-n catalyst for BPA is 128 and 13.8 times higher than that of BiOBr and BiOI, respectively. The excellent degradation activity benefits from the suitable energy band potential, interior electric field and superior charge separation efficiency. The test of catalytic cycles confirms the high reusability of BiOBrnI1-n. Photoinduced h+, ·O2−, and e− serve as reactive species in the degradation process. This work provides an effective photocatalyst for the photodegradation of various contaminants.

Fully Integrated Direct Current Triboelectric Nanogenerators Coupled with Charge Pump and Electric Field Enhancing Effect Enabling Improved Output Performance

AbstractDirect‐current triboelectric nanogenerators (DC‐TENGs) arising from electrostatic breakdown have garnered significant attention due to their advantages of rectification‐free operation, constant current output, and high output power density. Previous studies have primarily concentrated on improving its performance through structural design and parameter optimization, neglecting the potential benefits of external charge excitation. Here, a facile and universal strategy coupling charge pump and electric field enhancing effect with DC‐TENG (CE‐DC‐TENG) is proposed to improve the output performance of DC‐TENG. An alternating current TENG is used as the charge pump. A field‐enhancing conductive layer, which is introduced under the main DC‐TENG, is connected with the pump TENG to accumulate the charge and enhance the electric field for electrostatic breakdown. The effectiveness of this method is demonstrated by linear and rotary sliding mode TENGs. Furthermore, a fully integrated rotary sliding mode CE‐DC‐TENG is designed and fabricated, and it exhibits impressive performance with a 13‐fold higher power density of 1.56 W m−2 compared to conventional DC‐TENG. Moreover, it can directly power small electronics or be combined with a designed power management circuit for more efficient energy conversion. This work presents a new design strategy for improving the performance of DC‐TENG and facilitating its practical applications.

A 3D Numerical Model to Estimate Lightning Types for PyroCb Thundercloud

Pyrocumulonimbus (pyroCb) thunderclouds, produced from extreme bushfires, can initiate frequent cloud-to-ground (CG) lightning strikes containing extended continuing currents. This, in turn, can ignite new spot fires and inflict massive harm on the environment and infrastructures. This study presents a 3D numerical thundercloud model for estimating the lightning of different types and its striking zone for the conceptual tripole thundercloud structure which is theorized to produce the lightning phenomenon in pyroCb storms. More emphasis is given to the lower positive charge layer, and the impacts of strong wind shear are also explored to thoroughly examine various electrical parameters including the longitudinal electric field, electric potential, and surface charge density. The simulation outcomes on pyroCb thunderclouds with a tripole structure confirm the presence of negative longitudinal electric field initiation at the cloud’s lower region. This initiation is accompanied by enhancing the lower positive charge region, resulting in an overall positive electric potential increase. Consequently, negative surface charge density appears underneath the pyroCb thundercloud which has the potential to induce positive (+CG) lightning flashes. With wind shear extension of upper charge layers in pyroCb, the lightning initiation potential becomes negative to reduce the absolute field value and would generate negative (−CG) lightning flashes. A subsequent parametric study is carried out considering a positive correlation between aerosol concentration and charge density to investigate the sensitivity of pyroCb electrification under the influence of high aerosol conditions. The suggested model would establish the basis for identifying the potential area impacted by lightning and could also be expanded to analyze the dangerous conditions that may arise in wind energy farms or power substations in times of severe pyroCb events.

Effect of an Adiabatic Obstacle on the Symmetry of the Temperature, Flow, and Electric Charge Fields during Electrohydrodynamic Natural Convection

This study explores the impact of an adiabatic obstacle on the symmetry of temperature, flow, and electric charge fields during electrohydrodynamic (EHD) natural convection. The configuration studied involves a square, differentially heated cavity with an adiabatic obstacle subjected to a destabilizing thermal gradient and a potential difference between horizontal walls. A numerical analysis was performed using the finite volume method combined with Patankar’s “blocked-off-regions” technique, employing an in-house FORTRAN code. The study covers a range of dimensionless electrical Rayleigh numbers (0 to 700) and thermal Rayleigh numbers (102 to 105), with various obstacle positions. Key findings indicate that while the obstacle reduces heat transfer, this can be counterbalanced by electric field effects, achieving up to 165% local heat transfer improvement and 100% average enhancement. Depending on the obstacle’s position and size, convective transfer can increase by 27% or decrease by 21%. The study introduces five multiparametric mathematical correlations for rapid Nusselt number determination, applicable to numerous engineering scenarios. This work uniquely combines passive (adiabatic obstacle) and active (electric field) techniques to control heat transfer, providing new insights into the flow behaviour and charge distribution in electro-thermo-hydrodynamic systems.

Detection of defect-induced luminescence in epoxy-based insulation materials via phase-resolved photon counting method

Electroluminescence (EL) has shown promise in detecting micro-defects in epoxy-based insulation materials. Understanding the various luminescence mechanisms caused by defects is crucial for improving the characterization and analysis of insulation defects. In light of this, this study proposes a photon counting-based approach to investigate the impact of defects on the entire evolutionary process of the luminescence mechanism. A phase-resolved photon counting (PRPC) method is proposed to examine the polarity and periodicity of photon counting results influenced by defects. Additionally, a simulation model based on the finite element method is established to analyze how defects modify the distribution of electric field and space charges. Observations suggest that the PRPC-based approach holds promise for advancing the defect analysis of epoxy insulation used in gas-insulated equipment.

Doping-control of excitons and magnetism in few-layer CrSBr

Magnetism in two-dimensional materials reveals phenomena distinct from bulk magnetic crystals, with sensitivity to charge doping and electric fields in monolayer and bilayer van der Waals magnet CrI3. Within the class of layered magnets, semiconducting CrSBr stands out by featuring stability under ambient conditions, correlating excitons with magnetic order and thus providing strong magnon-exciton coupling, and exhibiting peculiar magneto-optics of exciton-polaritons. Here, we demonstrate that both exciton and magnetic transitions in bilayer and trilayer CrSBr are sensitive to voltage-controlled field-effect charging, exhibiting bound exciton-charge complexes and doping-induced metamagnetic transitions. Moreover, we demonstrate how these unique properties enable optical probes of local magnetic order, visualizing magnetic domains of competing phases across metamagnetic transitions induced by magnetic field or electrostatic doping. Our work identifies few-layer CrSBr as a rich platform for exploring collaborative effects of charge, optical excitations, and magnetism.

Study on space charge accumulation characteristics of silicone elastomer under DC voltage

AbstractThe electric field distortion caused by the accumulation of space charge in the insulating dielectric is easy to lead to accelerated ageing and even breakdown. In this paper, the space charge characteristics and the interfacial electric field change with time of silicone elastomer under different polarity DC voltages are studied. The results show that the homopolar charge injection is dominant in the silicone elastomer, and the electric field threshold is less than 4 kV/mm. The accumulation of homopolar charge weakens the interfacial electric field, resulting in the reduction of charge injection, and the interfacial electric field and spatial charge distribution gradually stabilise over time. In addition, the electric field at the interface does not decrease to the charge injection field threshold when it reaches stability. A time‐varying electric field model of the metal‐dielectric interface under a direct current field is derived and a calculation method for the time of charge accumulation to stabilise is proposed, based on the Schottky injection model and the relation between current density and volume charge density. The accuracy of the model is verified by comparing it with the experimental results of the stability time of silicone elastomer. This model is used to estimate the time when space charge accumulation reaches stability by means of the electric field threshold and the interface barrier, which can provide reference for the experimental measurement of space charge.

Numerical study on staggered needle-plate electrode configuration for improved particulate matter collection in electrostatic precipitator

The electrostatic precipitator (ESP) utilizes corona discharge to effectively separate particles from polluted air. The arrangement of electrode is a crucial role in achieving higher efficiency. Needle discharge electrodes can generate concentrated corona discharge at lower applied voltages. In this study, a staggered needle-plate electrode configuration was presented to expand the domain for particle charging, and thereby improve collection efficiency. A three-dimensional model was established to describe the multi-physics phenomenon in the ESP. The ion charge distribution, electric field, and particle collection efficiency were investigated under various conditions. The staggered model showed an average ion charge density that was 20% higher than that of the aligned arrangement. Particles introduced via staggered model acquired higher charge and showed improved collection efficiency across inflow velocities of 0.5 to 1.5 m/s and particle diameters of 0.1 to 50 μm. In the staggered model, particles predominantly escaped near the sidewall of the ESP.