Behavior Of Dielectric Barrier Discharge Research Articles

Study on the Physical and Chemical Characteristics of DBD: The Effect of N2/O2 Mixture Ratio on the Product Regulation

The chemical product behaviors of dielectric barrier discharge (DBD) in N2/O2 gas mixtures are investigated. Besides ozone mode and nitrogen oxides mode, a transitional mode in which O3 and NO2 coexist is observed. Under higher oxygen content condition, higher applied voltage and lower gas flow rate contribute to the appearance of the transitional mode. To further investigate the physical and chemical characteristics of DBD under different oxygen contents, the energy per area is introduced. It presents a positive relationship with applied voltage and a negative relationship with gas flow rate. And the energy per area of transitional mode is higher than that of ozone mode, but lower than that of nitrogen oxides mode. As the oxygen content rises, the critical energy per area of mode transition increases. Through the analysis of chemical products, it is found that higher oxygen content is beneficial to the generation of O3. The NO concentration is positively correlated with applied voltage. And the optimum applied voltage for obtaining the maximum NO2 concentration increases with the rise of gas flow rate. With respect to N2O, they are easier to be obtained at higher applied voltage and lower oxygen content under higher gas flow rate condition. And in the case of lower gas flow rate, lower applied voltage and higher oxygen content are beneficial to its generation. Besides, the maximum N2O5 concentration tends to be obtained at 50% oxygen content in the case of lower applied voltage and higher gas flow rate.

Particle-in-cell/Monte Carlo simulation of filamentary barrier discharges

The plasma behavior of filamentary barrier discharges in helium is simulated using a two-dimensional (2D) particle-in-cell/Monte Carlo model. Four different phases have been suggested in terms of the development of the discharge: the Townsend phase; the space-charge dominated phase; the formation of the cathode layer, and the extinguishing phase. The spatial-temporal evolution of the particle densities, velocities of the charged particles, electric fields, and surface charges has been demonstrated. Our simulation provides insights into the underlying mechanism of the discharge and explains many dynamical behaviors of dielectric barrier discharge (DBD) filaments.

Computational study of temporal behavior of incident species impinging on a water surface in dielectric barrier discharge for the understanding of plasma–liquid interface

A lipid bilayer is a basic structure of the cell membrane and is stable in liquid solution. In this study, we analyzed dielectric barrier discharge (DBD) containing water on a quartz substrate using a one-dimensional fluid model. To simulate atmospheric pressure plasma for practical use, a tiny amount of N2 gas (0.5 ppm) was added to He gas ambient as an impure gas. The calculated current–voltage (I–V) characteristics reproduced the measured ones qualitatively. We focused on the behavior of DBD at the plasma–liquid interface and analyzed the temporal behavior of the electric field strength and incident fluxes of charged, excited, and radical species on the water surface. By varying the gap length, it was shown that the maximum electric field strength in an AC cycle saturated at gap lengths ≥0.15 cm. The incident fluxes of N2+ and He2+ on the water surface are almost the same and show strong correlations with the electric field in the vicinity of the water surface.

Emission Spectroscopy and Energy Transfer Process in Atmospheric Dielectric Barrier Discharge in Oxygen

To investigate physical chemical behaviors of dielectric barrier discharge at atmospheric pressure in oxygen, the chemical active species which might exist in plasma were analyzed with the diagnosis technique of optical emission spectroscopy (OES) in oxygen discharge system. From the oxygen atom emission spectra in 500-950 nm, the electronic temperature was calculated by some atomic lines to be (1.02±0.03) eV. The oxygen atmospheric band O2 (b1Σ+g-X3Σ-g) in 760 nm was analyzed, and the rotational temperature (gas temperature) was calculated by its rotational structure to be (650±20) K. The first negative system O+2(b4Σ-g-a4Πu) in 500-700 nm and the Hopfield system O+2(c4Σ+u-b4Σ-g) in 190-240 nm were observed. The research showed that there were various reactive species in plasma of dielectric barrier discharge at atmospheric pressure in oxygen, such as a series excited oxygen atoms, excited oxygen molecules, ground and excited states of oxygen molecular ions. The formation of reactive species concerned many procedures of excitation, dissociation and ionization of oxygen, many energy transfer steps were included in every procedure. The oxygen atoms produced from oxygen molecule dissociation were ruling factor leading to generate reactive species besides electron.

Influence of dielectric parameters on temporal behavior of dielectric barrier discharge

The Influences of different temperature and materials of dielectrics on temporal behavior of dielectric barrier discharge in argon at atmospheric pressure are studied by using a device with asymmetric dielectric parameters. It is found that the temporal waveform of discharge current in each half cycle is almost the same at lower applied voltage, whereas the number of discharge current pulses is different in half cycles of different polarity at higher applied voltage. The analysis shows that both temperature and material of dielectrics affect the accumulation of wall charges, resulting in the change of temporal behavior of discharge.