Papers by Keyword: Corona Discharge

Abstract: In the present investigation, enhancement in the drying rate by an AC corona discharge from a single Copper (Cu) needle electrode was evaluated experimentally. The electrode generates corona wind (ionic wind), which impinges on, and eliminates moisture from the surface of a moist test sample. The corona discharge was generated by connecting the needle electrode to an alternating current (AC) power source. The drying sample consisted of 5mm soda lime glass beads saturated with water. Experiments were performed in the presence and absence of airflow over the drying samples, which were subjected to the corona discharge. The discharge was regulated, and experiments were conducted with 1 kV increments from the corona inception voltage till the sparkover occurred. Each experiment lasted for at least two hours and fifty minutes. The weight loss in the sample containers and the ambient temperature and relative humidity were all monitored. In each instance, a companion experiment was conducted concurrently. The results show that Copper (Cu) as an electrode material effectively influences the enhancement of an EHD drying process. With low-velocity cross-flow ( ) assisting in the drying enhancement.

Abstract: The removal of trichloroethylene (TCE) by corona discharge plasma was investigated. The influences of initial concentration, gas flow rate, injection of water vapor and ozone (O₃) on removal efficiency were discussed. The results show that removal efficiency reduces with the initial concentration and gas flow rate increasing. A proper quantity of water vapor injection can improve the removal efficiency, but which is not always increased, due to the electronegative characteristic of water molecule. The maximum removal efficiency of 90.7% can be obtained in wet air flow with relative humidity of 70.6%. The removal efficiency increases obviously with O₃ injection. The decomposition products are 2,2-Dichloroacetyl chloride (CHCl₂COCl), carbonyl chloride (COCl₂), hydrogen chloride (HCl) and carbon dioxide (CO₂), based on which the decomposition mechanism is discussed. The oxygen chain reaction is the primary decomposition mechanism, and high energy electrons and active oxygen species play a leading role in the decomposition process. Therefore, removal efficiency of TCE can be improved greatly when water vapor and O₃ is injected.

Abstract: The plasma degradation process of Eosin yellow aqueous solution utilizing AC corona discharge generated above liquid with a type of pin to plate by utilizing multiple needles electrodesis investigated the influence of electrodes material and effect of ferrous sulfate on decoloration and the kinetics of process are discussed. The AC corona discharge plasma was generated in the air gap between tip of needles and the water surface. The experimental results indicate that the decoloration rate increases with using stainless steel electrodes and with increasing the concentration of FeSO₄. When dye concentration is 10 mg/L with pH of 3, the air gaps were 0.85 cm and the number of pins were 30, the decoloration rate went up to 97% in 60 min.

Abstract: The decomposition of ethanethiol by a corona radical injection system, using water vapor and O₃ as radical source, was investigated. It is found that only 83.6% of ethanethiol can be decomposed in dry air flow with relative humidity of 13.4%. A proper quantity of water vapor injection can improve the decomposition efficiency, but which is not always increased. The maximum decomposition efficiency of 99.1% can be obtained in wet air flow with relative humidity of 74.7%. 97.6% of ethanethiol can be decomposed when the relative humidity of gas flow is 51.6%, but it is found that only 76.3% of element sulfur is converted to SO₂, based on sulfur balance. However, the conversion efficiency of sulfur to SO₂ increases obviously with the increasing of O₃ injection. The decomposition efficiency of ethanethiol and conversion efficiency of sulfur to SO₂ can reach 99.8% and 95.3% respectively, when O₃ is injected into the reactor by high voltage electrode tubes with concentration of 1 g/m3 and flow rate of 300 L/h. The decomposition products are SO₂, CO₂ and H₂O, while no organic product is found, based on which the decomposition mechanism is discussed. The weakest chemical bond C-S in ethanethiol molecule is firstly decomposed to ·SH and ·C₂H₅ radicals. ·SH can be oxidized to elemental sulfur and SO₂, and ·C₂H₅ is oxidized to CO₂ and H₂O.

Abstract: The article considers the rules of constructing machining operations in terms of impact of the product lifecycle to choose operating sizes. A comprehensive optimality criterion is proposed. Technology combined method of surface hardening mixtures based on thermal impurities and its perspective value are shown.

Abstract: Study of EHD flow by using generator corona discharge with electrodes configuration of pin to multi concentric rings (MCR) and pin to single ring (SR) have been curried out. We measured the velocity of EHD flow and determined the comparison of velocity of EHD flow produced by pin to single ring electrodes. The pin needle was made by stainless steel with a length of 50 mm and a tip diameter of 0.14 mm. The multi-ring electrodes constracted by three concentric rings with a metal material connected to each other and each ring has a diameter of 24 mm, 16 mm and 8 mm in width and the same ring thickness is 2 mm and 3 mm. Single ring electrode has a diameter, width and thickness respectively 24 mm , 3 mm and 2 mm. EHD was generated by using a DC high voltage of 10 kV. Pin as an active electrode of corona discharge and concentric rings multi/single ring electrodes as ions collector and passive electrodes. The velocity of EHD flow was measured by a hot-wire anemometer. We found that the velocity of EHD flow with multi-ring concentric electrodes larger than a single ring electrode. The measurement of velocity for two cases of electrodes configuration were limited at the certain voltage due to breackdown and arc phenomena. The maximum velocity of the of EHD flow using a pin-multi rings concentric was 0.7 m/s at a voltage of 6 kV.

Abstract: With concern for chemicals leak in transportation, there is an urgent need for a sensor which can quickly and accurately detect chemicals. In this study, a high-sensitivity gas sensor was demonstrated, which is based on high-field asymmetric waveform ion mobility spectrometry technology with corona discharge (CD) used as the ionization source to product gas-phase ion samples, which can get the response in one second. The effects of dispersion voltage and moisture were investigated.

Abstract: In order to study the electromagnetic interference on SAW (surface acoustic wave) wireless temperature measurement system of the corona discharge, the paper analyzes the characteristics of the frequency spectrum of corona discharge, models the corona discharge and studies its radiation characteristics by simulation on Matlab. Based on this, the experimental platforms of corona discharge is set up. The result of the experiment confirms that corona discharge causes electromagnetic interference to the system and the influence decreases as the distance between the sensor and discharge sources increase. Then the sensor should be kept a certain distance from the discharge sources.

Abstract: In order to enhance the electromechanical performance of functional polymers for their application in the fields of robot, sensors, transducer and actuators etc., the high voltage corona discharge equipment has been used in this paper with the aim of injecting a large amount of electrons into the Porous Polypropylene (PP) and Polyvinyl Chloride (PVC). In addition, the performances of magnetoelectric effect of porous PP and PVC between before and after corona discharge have also been discussed for the first time. It is shown that their magnetoelectric current of porous PP and PVC can be increased by the corona discharge technique. We have established the fact that enhanced ME performance could be achieved by using effective corona poling method on porous polymer and not only by adding micro or nanoadditives.

Abstract: High-voltage insulator is a kind of common and important device in the grid, in the processing of its function, effections of various environmental factors will make its insulation to deterioration and decline, without timely treatment, the accumulated deterioration may lead to surface discharge, and even surface flashover, which will damage the insulation and greatly endanger the safety of power system. A method by accurately testing the ultraviolet intensity of insulators which is under the conditions of different deterioration and filthy is proposed on this basis, and depend on which we can provide evidences for finding early deterioration of insulators.