Modelling the Role of the Inner Electrode Radius on the Oxygen Negative Corona Discharge in Coaxial Electrode Geometry

The charge species plays a vital role in changing the field in direct current discharge (DC). This article introduces a numerical modeling in one dimension of the inner electrode diameter of oxygen-fed negative corona discharge in coaxial electrodes geometry. The properties of negative corona plasma in a concentric cylindrical electrodes (wire-cylinder) were simulated by COMSOL Multiphysics software. Various diameters of negative corona electrode, namely 0.01, 0.025, 0.05, 0.075, and 0.125 mm, were applied, ​​where the diameter of the outer cylindrical electrode was taken as 15 mm. The model was run at atmospheric pressure and the applied negative voltage was -10 KV. Moreover, oxygen gas was used to fill the inter-electrodes distance. Furthermore, the spatial distribution of electrons, positive ions, and negative ions as a function of the diameter of negative electrode of the negative corona discharge were investigated. The study also tested the effects of the electrode diameter of the negative corona discharge on ozone generation. The observed decrease in ozone density with the increase in negative electrode diameter was reasonable and consistent with other results provided by researchers in this field.

The Role of Nonlinear Body Force in Electrostatic Propeller Driven by Atmospheric DC Corona Discharges

In this study, the body force generated by atmospheric positive and negative corona discharges were investigated using a wire-cylinder configuration experimentally and numerically. We provided new insight into the atmospheric electric thruster by introducing a nonlinear term in body force constituent the thrust of the system. It was observed that the direction of both body forces and electric winds is always from the wire to the cylinder irrespective of the applied voltage polarity. It was illustrated that the corresponding thrusts and the electric wind of the positive corona are larger than that of the negative corona discharge. We took into account the nonlinear mechanisms to explain the difference in thrust forces in positive and negative corona discharges. To elucidate the origin of the body force in corona discharges, we performed 2-D simulations via COMSOL Multiphysics and MATLAB software. The results of the numerical simulation showed that in addition to the linear body force (Coulomb force) a strong nonlinear body force is generated around the wire electrode that plays a crucial role in corona thrusters. To verify the direction and magnitude of the thrust, a simple theory was proposed based on variable mass systems and confirmed by published experimental works.

Simulation of negative corona discharge in atmospheric air: from mode of Trichel pulses to stationary discharge

The paper presents a 2D multi-fluid non-stationary model of a negative corona discharge in atmospheric-pressure air in the needle-to-plane diode. Discharges were simulated in gaps up to 1 cm with an applied voltage in the range of 8-100 kV. The simulation results demonstrate two stages of the discharge evolution: a pulsed-periodic stage called the Trichel pulses mode and a stationary glow discharge mode. The spatio-temporal distributions of the discharge plasma and electric field are shown in detail. Physical mechanism of Trichel pulses formation and transition to the stationary discharge are also revealed. The duration of the Trichel pulse mode gradually decreases with increasing of the applied voltage.

ABOUT THE REASONS FOR THE CHANGE IN THE MECHANICAL PROPERTIES OF PAPER ASHLESS FILTERS DURING THEIR PROCESSING IN A UNIPOLAR CORONA DISCHARGE

The article presents the study results of the structure and properties of paper ashless filters "Blue tape". It is shown that the "Blue tape" filter paper has a fairly high density with a relatively small number and size of voids (pores) between the fibers. When processing filters in the corona discharge field, an increase in their mechanical properties by 3.5–6% is observed, this is mainly due to the strengthening of the interfiber bond forces. The implementation of increased electrostatic bonding forces in the sheet structure leads to an increase in the resistance to the external tensile force necessary to break the paper filter. The observed dependences are associated with the orientation and ordering of the pulp and paper material structural elements, with an increase in the potential of the double electric layer on the fibers surface under the charge action carriers injected into the paper volume from the corona discharge and with the formation of a hetero charge due to the orientation of the polar cellulose groups and macromolecule segments during electreting. This is confirmed by the increase in the ζ – potential of the fibers of filters during processing in a negative corona discharge - it was found that the zeta – potential value of electret ashless filters is 18% higher than for the initial ones. The achieved results of increasing the ashless filters physico- mechanical properties will increase the efficiency of their use.

EMISSION SPECTRA AND CURRENT CHARACTERISTICS OF NEGATIVE CORONA DISCHARGE IN AN ELECTRODE SYSTEM WITH LIQUID ANODE

Experimental study of emission spectra and current characteristics of negative corona discharge over the surface of aqueous salt solutions have been carried out. The radiation spectra from the active zone of the discharge in the wavelength range 200…600 nm were obtained and identified. It was found that most of the spectral lines correspond to the lines of second positive system of molecular nitrogen. The spectral lines of the nitrogen ion N2+ and the lines corresponding to the emission of the OH radical in the UV spectral region are also observed. Current-voltage characteristics of the discharge were obtained at the non-stationary and diffuse stages of the discharge. It was shown that obtained current-voltage characteristics are in good agreement with the results of theoretical calculations using the Townsend expression.