Journal of Electrostatics最新文献

The circuit oscillation generated during the process of pulsed arc electrohydraulic discharge can prolong the discharge time and pose potential hazards to the withstand voltage of the discharge equipment. To enhance the anti-oscillation performance of the equipment, the structure of the gas spark switch was analyzed and an improved pulse power switch for suppressing circuit oscillation was designed. Firstly, a two-dimensional axisymmetric simulation model of the gas spark switch was established by COMSOL software, and a theoretical model to express the impedance of the plasma channel through the series combination of resistance and inductance was put forward. Then, the correctness of the theoretical model was proved by the nonlinear regression method considering the capacitance effect of plasma discharge, and the results show that the theoretical model almost coincides with the actual discharge waveform, with a fitting rate of 99.73%. Finally, a thyristor-based pulse power switch was designed, and an electrohydraulic discharge experiment was carried out. The experimental results show that the designed switch can reliably control the output of the high-voltage pulses even if the repetitive discharge frequency is higher than 60 Hz under 8.5 kV voltage. Furthermore, the circuit oscillation process was suppressed, and the oscillation time was reduced from 242μs to 39 μs, with a decrease of 83.88 %. This study has potential application value in underwater high-voltage discharge applications.

This paper proposes the general design of a Wet Electrostatic Scrubber aimed at mitigating fine and ultrafine particles emissions from domestic heating boilers. The design is based on particle capture modelling supported by specific experiments and technical literature information. Results indicate up to 96.6% removal efficiency, consuming 1.2 kg/h of water and 0.3 W per 1 m³/h of gas treated. Comparative analysis highlights the balanced performance of Wet Electrostatic Scrubber in particle capture, energy and water usage, pressure drop, and space occupancy, with the additional benefit of more efficient absorption of gas pollutants.

The epidemiological information concerning novel corona virus (SARS-Cov-2) seeks attention nowadays to get an overview of global as well as country-based cases and deaths so far. The utilization of face mask has become evident for the protective measure of mankind to filter out the infiltrating virus from outside. In this paper, we have analysed various triboelectric based energy harvester configurations focusing on its application in self-powered smart mask design to combat SARS-Cov-2. Smart mask will comprise of triboelectric nanogenerator (TENG) and a smart layer to execute electrocution of the infiltrating virus as well as ensure the safety of human being (I < 10 mA). The theoretical investigations and simulation studies are carried out for different triboelectric materials and a comparative analysis is also portrayed in the context of designing self-powered smart mask under different operating modes. It has been observed that polypropylene-poly methyl methacrylate (PP-PMMA) material combination produces an electrical field of 0.9916 MV/m which is sufficient to electrocute the virus without causing harm to human body. Hence the design and comprehensive analysis is carried out considering PP-PMMA combination for various possible modes of operation like constant velocity, constant acceleration, sinusoidal and generic one. Here, respiration is considered as major mechanical input source for TENG whereas other biomechanical activities like talking, chewing are also discussed in the context of self-powered application of smart mask. It has been demonstrated that the physiological activity like chewing and respiration altogether produce a typical input force of 23.65 N which is sufficient to electrocute the incoming virus without causing any hazard to human health.

A newly designed voltage treatment chamber for AC electric field application with high voltage transformer, voltage divider, over current limiter, and vacuum treatment chamber was utilized to treat red beetroot samples by 0.00–11.5 kV, 400–1013 mbar, and 18.15–20.00min. Applied processing parameters caused a significant increase in the total antioxidant capacity. The best-fit multiple (non-) linear regression models with response optimization revealed 4.6 kV, 400 mbar, and 30.90% moisture as the most optimal processing parameters with 0.8313 composite desirability. Application of electric fields may be utilized for the electroporation of the plant tissue without adverse effect on important properties.

The electric potential and field of a finite conducting rod are calculated. This is done by two methods. In the first, ellipsoidal coordinates are used to solve the Laplace equation outside the rod. In the second, asymptotic behavior of the electric field is used to find the position-dependence of the change density on the rod, which is then used to calculate the potential and field. An analytic continuation is performed to relate this problem to that of a conducting disk. Using this, the electric potential and field of a disk are determined. The charge densities are also calculated.

In a quiescent environment, dielectric barrier discharge (DBD) plasma actuators generate a wall jet through the interaction of ionized and neutral molecules in an electric field. In external flow, the coupling between electrohydrodynamic (EHD), turbulence, inertial, and viscous effects in the flow boundary layer is more complex and requires additional investigation. We experimentally study momentum injection by DBD actuators into the free stream flow with Re = 35,000 and 75,000 in co-flow and counter-flow scenarios over a range of V_AC = 12 kV–19.5 kV peak-to-peak at a frequency of 2 kHz. In co-flow, the momentum injection leads to boundary layer thinning and fluid entrainment from the freestream into the DBD forcing region, while in the counter-flow configuration, flow separation can occur. A separation bubble is observed at Re = 35,000 for the tested condition. The momentum difference in the counter-flow configuration is six times greater than the EHD jet momentum in a quiescent environment. Both co-flow and counter-flow momentum injections show diminishing effects with higher Re. We show that the resulting flow pattern is not a superposition of the EHD jet and the free stream but is determined by the coupling and competition of inertial, viscous, and Coulombic effects between the EHD-driven forcing and the external flow. The proposed non-dimensional momentum ratio (M*) of EHD jet momentum to momentum in the external flow boundary layer can be used to predict the onset of separation; however, additional experimental and numerical studies are required to generalize this concept to other flow scenarios. The velocity profiles and momentum measurements presented here can be used to validate numerical models and inform the design of DBD actuators for active flow control.

Accurate determination of the electrostatic force exerted on multipole moments is essential in comprehending the interaction between charged bodies and dielectric layers. A comprehensive solution is presented in this study for the calculation of the electric potential, field, and force generated by nth-order electric multipole above a semi-infinite dielectric body covered by a dielectric layer using the image multipole method. The present study investigates the impact of dielectric thickness, permittivity, and separation distance on the electrostatic interaction between an electric multipole moment and a semi-infinite dielectric body. The calculation results indicate that as the thickness of the dielectric layer increases and the dielectric constant of the surrounding medium surpasses that of the dielectric layer, the electrostatic attractive force undergoes a transition to a repulsive force. The magnitude of the electrostatic force acting on a nth-order electric multipole moment is directly proportional to the square of the value of the electric multipole moment and inversely proportional to the 2 (n+1) power of the distance.

Numerical values of electrostatic properties of the cube are well investigated whereas numerical ones of the square plate are not. In this paper, we update the numerical values of electrostatic properties of the unit square plate, such as the capacitance, and the edge and corner singularity exponents. For the capacitance, we use the refined Brownian dynamics algorithm with “walk-on-planes” (WOP) method (a kind of first-passage algorithm) and for the edge singularity and corner exponents, the sphere last-passage algorithm.

This study investigates particle dynamics impacting a charged spherical collector through experiments and simulations, revealing the influence of the collector’s non-uniform potential field. Electrostatic and drag forces govern trajectories, while gravity and dielectrophoretic forces play a minor role. Positive electrostatic and negative drag work are comparable, offering critical insights into particle energy budgets. Closer proximity to the collector center leads to a greater energy budget, causing uneven particle collection. Analysis of fractional energy loss indicates a critical point where electrostatic work dominates over viscous dissipation. This analysis is crucial for analyzing particle deposition behavior in non-uniform electric fields.

—When the particles are in the gas-solid two-phase flow, the transferred charge will be generated. The transferred signal obtained by using the inner flush-mounted electrostatic sensor is rich in flow information, which can provide important support for studying the flow law of gas-solid two-phase flow. In this paper, the nonlinear time-domain analysis method based on embedded empirical mode decomposition (EEMD) and largest Lyapunov exponent (LLE) is proposed to extract the transferred charge signal of gas-solid two-phase flow. Firstly, the electrostatic signal is decomposed and the induced charge signal is removed by the combination of EEMD and autocorrelation function correlation coefficient index. Then, the LLE of the remaining intrinsic mode function (IMF) components is calculated, and the corresponding IMF is selected to reconstruct into the transferred charge signal according to the condition that LLE>0. The results show that the LLE of transferred charge signal increases with the increase of the superficial gas velocity and decreases with the increase of solid gas mass ratio. The root mean square (RMS) and standard deviation (STD) of the transferred charge signal increase with the increase of the superficial gas velocity, increase with the increase of the solid gas mass ratio, and slow down at high solid gas mass ratio.