Gliding Arc Discharge Plasma Research Articles

Functionalisation of titanium alloy surface through oxygen gas jet-assisted gliding arc discharge plasma

A modified surface layer was fabricated on Ti–6Al–4V samples by gliding arc discharge plasma assisted with an oxygen jet gas under atmospheric conditions. The oxidation reaction on the sample surface was promoted by active species with strong oxidising performance, such as oxygen and hydroxyl radicals. An amorphous titanium oxide layer was detected on the generated surface. The oxygen diffusion layer penetrated the substrate to an approximate depth of 500 nm. The generated surface exhibited higher biological cell adhesiveness and a lower elution amount of metal ions than the untreated sample surface.

Hydrophobization of cotton fabric by Gliding Arc plasma discharge

The surface modification in order to obtain hydrophobic cotton fabrics was carried out using air/HMDSO Gliding Arc plasma discharge. The dependence of the surface wettability on used process parameters, such as air flow, sample distance and treatment time were investigated. The wettability of cotton fabrics was evaluated by the drop test method by measuring the time of droplet absorption and water contact angle (WCA). The changes in the surface morphology were examined by optical microscopy and scanning electron microscopy (SEM). The treated hydrophobic fabrics were subjected to the analysis of chemical composition of the applied coatings using the ATR-FTIR spectroscopy. Hydrophobic cotton fabrics were obtained, especially with a high resistance to static wetting. In addition, the treated cotton fabrics were tested using a spray test measurement and were subjected to multiple washing.

Atmospheric pressure gliding arc discharge plasma treatments for improving germination, growth and yield of wheat

Wheat (Triticum aestivum) seeds were treated with atmospheric pressure gliding arc discharge plasmas to investigate the effects on water absorption, seed germination rate, seedling growth and yield in wheat. The surface architectures and functionalities of the seeds were found to modify due to plasma treatments. 6 min treatment was provided 95%–100% germination rate. For the treatment duration of 3 and 9 min the growth activity, dry matter accumulation, leaves chlorophyll contents, longest spikes, number of spikes/spikelet and total soluble protein content in shoots were improved. The grain yield of wheat was increased ∼20% by 6 min treatment with H2O/O2 plasma with respect to control.

Effect of pressure on the properties and species production in gliding arc Ar, O2, and air discharge plasmas

A gliding arc discharge (GAD) plasma is generated inside a vacuum chamber with Ar, O2, and air at pressure 100–600 Torr driven by a 1 kHz, 3–6 kV power supply. The properties of the GAD plasma are investigated by electrical and optical emission spectroscopy methods. The power dissipation, relative intensity, jet length, rotational ( Tr) and excitational (Tex) temperatures, and electron density (ne) are studied as a function of applied voltage, pressure, and feeding gas. It is found from the electrical characteristics that the power dissipation shows decreasing trends with increasing pressure but increasing with increasing voltage. The relative population densities of the reactive species N2(C−B), O, and OH radicals produced as functions of pressure and applied voltage are investigated. It is found that the relative population densities of the species, especially N2(C−B) and O, are increased with applied voltage and pressure, while OH(A-X) is decreased. The spectroscopic diagnostics reveals that Tr≈550–850 K, Tex≈8200–10 800 K, and ne≈2.65–5.3×1014 cm−3 under different experimental conditions. Tr and ne are increased with increasing pressure, while Tex is decreased.

Experimental investigation on gliding arc discharge plasma ignition and flame stabilization in scramjet combustor

Ignition and flame stability in supersonic flow have always been the key problems of research in scramjet. In addition, ignition is difficult and the cavity flameholder is susceptible to support the flame stability under extreme conditions such as low equivalent ratio. In recent years, gliding arc plasma is recognized to expand ignition and extinction limit with lower energy consumption in the field of plasma assisted ignition due to its heating and chemical effects. In this paper, a gliding arc igniter has been designed and compared with the traditional spark plug in order to quantify the ignition ability. The igniter has the same size with the spark plug, using low-power AC gliding arc to carry out ethylene ignition test in Ma = 2.52 Ma supersonic flow. The average power of gliding arc discharge is 1199 W. A high-speed camera and CH⁎ chemiluminescence were used to make combustion diagnosis. Founded in the same discharge period, the lean ignition limit of the gliding arc is lower than the ignition limit of the spark. The average expansion of ethylene ignition limit is 17%. The ignition process is that gliding arc continues to generate the initial flame kernels during the discharge period, but it is extinguished continuously due to the strong convection. Until generating an initial flame kernel which can successfully propagate the flame. The ignition process can be divided into four stages. It continues to generate new flame kernels in flame propagation process. Gliding arc reignites the fuel and generates the new flame kernels after forming a stable flame, appearing intermittent ignition in the cavity. The high equivalent ratio can make ignition delay time shorter, generating initial flame kernels more frequently. The heating effect of the gliding arc and reignition character make the thermal product and ethylene occur intermittent combustion more often in the cavity, increasing the area of the combustion reaction. Gliding arc plasma can achieve combustion enhancement during the flame stabilization process. The shear layer of flame thickness increased by the average of 2 mm on S-B-1 and G-B-1 conditions. Compared with the traditional spark ignition, gliding arc broaden the lean blow-off limit in different stages may be the significant reason for broadening lean ignition limit. It concludes that gliding arc makes the flame's ignition limit closer to the flame's blow-off limit.

OH and O radicals production in atmospheric pressure air/Ar/H2O gliding arc discharge plasma jet

Atmospheric pressure air/Ar/H2O gliding arc discharge plasma is produced by a pulsed dc power supply. An optical emission spectroscopic (OES) diagnostic technique is used for the characterization of plasmas and for identifications of and radicals along with other species in the plasmas. The OES diagnostic technique reveals the excitation Tx ≈ 5550–9000 K, rotational Tr ≈ 1350–2700 K and gas Tg ≈ 850–1600 K temperatures, and electron density under different experimental conditions. The production and destruction of and radicals are investigated as functions of applied voltage and air flow rate. Relative intensities of and radicals indicate that their production rates are increased with increasing content in the gas mixture and applied voltage. reveals that the higher densities of and radicals are produced in the discharge due to more effective electron impact dissociation of and molecules caused by higher kinetic energies as gained by electrons from the enhanced electric field as well as by enhanced The productions of and are decreasing with increasing air flow rate due to removal of Joule heat from the discharge region but enhanced air flow rate significantly modifies discharge maintenance properties. Besides, significantly reduces with the enhanced air flow rate. This investigation reveals that plays a significant role in the production of and radicals.

A New and Simple Approach for Decontamination of Food Contact Surfaces with Gliding Arc Discharge Atmospheric Non-Thermal Plasma

In this study, a gliding arc discharge (GAD) microplasma system was designed, and its decontamination effect was investigated on stainless steel (SS), silicone (Si), and polyethylene terephthalate (PET) surfaces artificially contaminated with 8.15 ± 0.28 log cfu/mL of Escherichia coli and 6.18 ± 0.21 log cfu/mL of Staphylococcus epidermidis. Each of the contaminated surfaces was treated with high purity air (79% nitrogen and 21% oxygen) or nitrogen plasmas for 1–10 min at varying rates of gas flow. Significant reductions of 3.76 ± 0.28, 3.19 ± 0.31, and 2.95 ± 0.94 log cfu/mL in S. epidermidis, and 2.72 ± 0.82, 4.43 ± 0.14, and 3.18 ± 0.96 log cfu/mL in E. coli on SS, Si, and PET surfaces, respectively, were achieved after 5 min of plasma treatment by using nitrogen as the plasma forming gas (p < 0.05). The temperature changes of each surface during plasma generation were lower than 35 °C and were not affected by the type of plasma forming gas. Additionally, morphological changes in the structure of E. coli and S. epidermidis after GAD plasma treatments were demonstrated using scanning electron microscopy (SEM).

Dimensionless factors for an alternating-current non-thermal arc plasma

A gliding arc discharge, as a source of warm plasma combining advantages of both thermal and cold plasmas, would have promising application prospects in the fields of fuel conversion, combustion enhancement, material synthesis, surface modifications, pollution control, etc. In order to gain insight into the features of an alternating-current gliding arc discharge plasma, three dimensionless factors, i.e., the extinction span (ψ), current lag (δ), and heating lag (χ) factors are proposed in this letter based on the measured waveforms of the discharge voltage and current in an AC gliding arc discharge plasma. The influences of the driving frequency of the power supply (f) on these three dimensionless parameters are investigated experimentally with the explanations on the physical meanings of these factors. The experimental results show that a higher value of f would lead to the lower values of ψ and δ, as well as a higher value of χ. These experimental phenomena indicate a lower threshold ignition voltage of the discharges, a lower current-growth inertia of the gliding arcs and a larger relative thermal inertia of the plasmas with increase the driving frequency of the power supply in the operating parameter range studied in this letter.

Non-equilibrium plasma prevention of Schistosoma japonicum transmission.

Schistosoma japonicum is a widespread human and animal parasite that causes intestinal and hepatosplenic schistosomiasis linked to colon, liver and bladder cancers, and anemia. Estimated 230 million people are currently infected with Schistosoma spp, with 779 million people at risk of contracting the parasite. Infection occurs when a host comes into contact with cercariae, a planktonic larval stage of the parasite, and can be prevented by inactivating the larvae, commonly by chemical treatment. We investigated the use of physical non-equilibrium plasma generated at atmospheric pressure using custom-made dielectric barrier discharge reactor to kill S. japonicum cercariae. Survival rate decreased with treatment time and applied power. Plasmas generated in O2 and air gas discharges were more effective in killing S. japonicum cercariae than that generated in He, which is directly related to the mechanism by which cercariae are inactivated. Reactive oxygen species, such as O atoms, abundant in O2 plasma and NO in air plasma play a major role in killing of S. japonicum cercariae via oxidation mechanisms. Similar level of efficacy is also shown for a gliding arc discharge plasma jet generated in ambient air, a system that may be more appropriate for scale-up and integration into existing water treatment processes.

Electrical Characteristics of Nonthermal Gliding Arc Discharge Reactor in Argon and Nitrogen Gases

Gliding arc discharge (GAD) has the properties of both thermal and nonthermal plasma conditions. GAD plasma in the atmospheric pressure with argon/nitrogen and its characteristics are described. Some experimental results about alternating current gliding arc plasma generator have been obtained. It seems that the current density strongly depends on the gas type, and increased with increasing discharge current and gas flow rate. In addition, the discharge current of GAD in nitrogen gas (N2) is greater than one in argon gas (Ar) because of N2 needs more breakdown voltage than Ar. The intensity of GAD increased with increasing the gas flow rate. The oscillograms of discharge current in each case of Ar and N2 were obtained. The electron temperatures of Ar and N2 plasma were calculated to be 22 800 and 8400 K, respectively. The characteristics of both Ar and N2 gases in atmospheric pressure, such as current density, electron density with flow rates (5, 10, 20, and 40) standard cubic foot per hour, were investigated and all experimental results were classified. An experimental study was carried out through using of GAD device for medical treatment by exposing three human blood samples of leukemia to the nonthermal GAD plasma for different periods.

Degradation of Reactive Blue 19 using advanced oxidation methods: gliding-arc plasma discharge

AbstractAqueous solutions of Reactive Blue 19 (RB19) were treated using advanced oxidation process (AOP) to remove the color from the water. The AOP process was applied using a non-thermal gliding-arc plasma discharge with and without the addition of hydrogen peroxide, H2O2, to the samples. The gliding-arc experiments were conducted in an open reactor using humid compressed air. Treating 20-ppm solutions without using H2O2 was successful in reducing the RB19 concentration but resulted in the increase of a secondary byproduct. With the use of H2O2, a higher RB19 removal rate was achieved and the byproduct production was avoided. The pH and conductivity measurements indicated the presence of a higher rate of reactive species when H2O2 was used. By treatment of the samples for 60 min, an RB19 removal rate of 87% was achieved when no H2O2 was used and an RB19 removal rate of 98.9% was achieved when H2O2 was added. Samples treated without the addition of H2O2 exhibited an additional post-discharge reaction in ...

Degradation of Verapamil hydrochloride in water by gliding arc discharge

This study investigated the influence of gliding arc plasma discharge on the degradation of Verapamil hydrochloride in water. The plasma discharge was characterized by means of optical emission spectroscopy. Spectra of various atomic and molecular species were observed. Aqueous solution of Verapamil hydrochloride was exposed to gliding arc discharge operated in continuous discharge at atmospheric pressure and room temperature. The identification of Verapamil, the degradation mechanisms of Verapamil and its transformation products were performed using liquid chromatography – mass spectrometry (HPLC-MS). Experimental results indicate that the atmospheric pressure gliding arc plasma treatment has noticeable effects on Verapamil with satisfactory degradation efficiency. Plausible mechanisms of the degradation were discussed.

Enhanced hydrogen production by methanol decomposition using a novel rotating gliding arc discharge plasma

Hydrogen production from methanol decomposition was performed in a novel direct current (DC) rotating gliding arc (RGA) plasma reactor.

Hydrogen Production from Methanol Decomposition in a Gliding Arc Discharge Plasma with High Processing Capacity

Herein, we report a simple and efficient method of hydrogen production from methanol decomposition using a gliding arc discharge (GAD) plasma. A maximum methanol conversion of 87.1% can be achieved...

Impulse Three Phase Power Supply Used for a Gliding Plasma Discharge

Power sources used for generating plasma have different configurations depending on the particular application; the aim here comprises the maximum energy transfer to the plasma discharge reaching. This work shows the performance and versatility of a simple impulse phase power source, applied to gliding arc plasma discharge. It is capable of changing the operating frequency from 5 kHz up to 150 kHz and the duty cycle from 1% to 33% in all three phases, each one connected to three divergent tungsten electrodes. This allows a soft start plasma ignition until the full load is reached. This converter uses a sequential logic circuits composed by flip-flops, gates drivers, IGBT's and high voltage ferrite transformers. These features facilitate the maximum energy transfer to the plasma without using more complex electronic structures. The effect of frequency, duty cycle, voltage and current wave form signals is here described. This power supply has the adaptability to work whit different type of gas such as Argon, Helium, Air and Nitrogen. A Matlab Simulink simulation validates the experimental results. The main features and advantages of this configuration are also defined.

DISCHARGE CHARACTERISTICS OF GLIDING ARC PLASMA REACTOR WITH ARGON/NITROGEN

Gliding Arc Discharge plasma has properties of both thermal and non-thermal plasma conditions. Gliding arc discharge plasma in the atmospheric pressure with argon/nitrogen and its characteristics are described. Some experimental results about alternating current gliding arc plasma generator have been obtained. It seems that the current density strongly depends on the gas, and increased with increasing discharge current and gas flow rate. Also, the discharge current of gliding arc Discharge plasma in Nitrogengas is greater than one in Argon gas because of Nitrogen gas need to higher breakdown voltage than Argon gas. The intensity of gliding arc discharge plasma increased with increasing the gas flow rate. In addition to the oscillograms of discharge current in each case of Argon &amp; Nitrogen were obtained. Electron temperatures of Argon and Nitrogen plasma were calculated to be 22800 K, 8400 K. The characteristics of both Argon &amp; Nitrogen gases in atmospheric pressure were investigated like current density, electron density with flow rates (5, 10, 20, and 40) Standard Cubic foot per Hour. All the experimental results were tabulated.

Enhanced discolouration of methyl violet 10B in a gliding arc plasma reactor by the maghemite nanoparticles used as heterogeneous catalyst

This study focuses on the discolouration of a triphenylmethane dye (i.e. methyl violet 10B) using a gliding arc plasma discharge in humid air. The results show that the discolouration process is strongly dependent on the initial dye concentration. The maximum discolouration rates are 96.9% and 6.7% after 60min for initial dye concentrations of 2.5mgL−1 and 100mgL−1, respectively. The incorporation of maghemite (γ-Fe2O3) into a 100mgL−1 dye solution increases the discolouration rate under plasma up to 55.6%. This improvement of the discolouration efficiency suggests that maghemite acts as a heterogeneous catalyst for Fenton decomposition of H2O2 resulting from the dimerization of HO radicals produced by plasma in the gas phase. The X-ray diffraction (XRD) and Fourier transform-infrared (FTIR) characterizations of the catalyst before and after being used 3-times show that the maghemite nanoparticles are stable in the target-solution exposed to gliding arc plasma and can be therefore reused for further treatments.

Decomposition of ammonia and hydrogen sulfide in simulated sludge drying waste gas by a novel non-thermal plasma

To efficiently clean NH3 and H2S contained in municipal sewage sludge drying waste gas, experiments were conducted with a novel gliding arc discharge plasma reactor. Important parameters including applied voltage and gas velocity which can strongly influence the removal efficiency, energy cost and by-products yields were investigated. Maximum removal efficiencies were all obtained at the applied voltage of 11kV and gas velocity of 4.72ms−1. When NH3 and H2S were treated together, the total energy cost decreased by 38%. NO and SO2 were observed as main decomposition by-products, and the presence of NH3 may inhibit the production of SO2 whose yield decreased from 223.8 to 27.8mgm−3. Tests performed on lab scale reactor showed that gliding arc discharge is efficient in decreasing the NH3 and H2S concentrations, and experiments will also be conducted on a larger scale reactor in the future.

Decontamination of Bacteria by Gas-Liquid Gliding Arc Discharge: Application to &lt;inline-formula&gt; &lt;tex-math notation="TeX"&gt;\(Escherichia~coli\) &lt;/tex-math&gt;&lt;/inline-formula&gt;

This paper investigated the bacterial inactivation/sterilization effects of a gas-liquid gliding arc discharge reactor, which created plasma at atmospheric pressure and ambient temperature. Bacteria Escherichia coli were subjected to plasma treatment and the survivability was examined. With the bacteria suspension circulated at defined flow rate, the E. coli cells were almost killed in <;3 min. The inactivation efficiency with circulation was much higher than that with no circulation, and it could even reach a reduction of 7 logarithm units in the number of viable bacteria within 30 s after 1-min treatment. Flow rates of the suspension caused slightly impact on the bacteria inactivation to a certain extent. Observations of scanning electron microscopy images helped to draw a conclusion that gas-liquid gliding arc discharge plasma acts under various mechanisms driven essentially by oxidation and electric effect. The results demonstrate that gas-liquid gliding arc discharge allows a rapid and complete inactivation of E. coli bacteria in the water, which shows the great industrial interest of gliding arc discharge technique for decontamination.

Plasma dissociation of H2S with O2 addition

The process of hydrogen sulfide, H2S, dissociation with oxygen addition was studied in a gliding arc plasma discharge. The goal of the study was to develop a plasma process that could demonstrate increased H2S conversion, reduced specific energy requirement (SER), and similar H2 yield when compared with plasma dissociation of pure H2S. The minimum SER of H2 production was found to be 1.0 eV/molecule at atmospheric pressure, 14 L/min H2S and 2.8 L/min O2 flow rates, and specific energy input (SEI) of 0.29 eV per H2S molecule. At the same conditions, the minimum SER of H2S destruction was found to be 0.43 eV/molecule, while hydrogen yield was observed to be 27%, water production was observed to be 38%, H2S destruction was observed to be 65%, and no measureable SO2 was detected. These results confirm the ability to reduce energy cost for H2 production while increasing H2S destruction in the system without sacrificing production of H2. This is very desirable from an industrial standpoint, where the processing and recycling of H2S is a very costly process.