Enhancement of positive pulsed corona by dielectric enclosure

Xingxing Wang,Andrei Khomenko,Alexey Shashurin

doi:10.1063/1.5117830

Abstract

In this work, the effect of positive pulsed corona enhancement by introducing Teflon dielectric enclosure in vicinity to the electrode assembly was studied. The discharge operating in air without the dielectric was able to operate within a very narrow voltage range of approximately 200 V. The pulsing frequency was below 1.2 kHz and current peaks were below 14 mA. Increasing the applied voltage onto the positive electrode beyond this range would result in sparks between the electrodes. When the Teflon tube enclosure surrounding the high voltage electrode was used, the window of stable pulsed corona operation expanded up to 3-5 kV. The pulsing frequency increased up to 12 kHz and the current peak level increased to approximately 35 mA. Increasing voltage beyond the point with peak pulsing frequency would result in a drop of pulsing frequency until the discharge pulsations stopped completely. The Teflon enclosure was able to enhance the average power deposited into the discharge from 10 to 220 mWatt. In addition, the product gases of the enhanced pulsed corona were tested to be mostly ozone with traceable amount of NO2. The discharge used about 150 eV and 1950 eV per one ozone molecule and nitrogen dioxide molecule respectively. The reported here plasma source is promising from the power density/compactness standpoint since significant enhancement (&gt;20 times) of the energy deposition to the discharge can be achieved compared to that of conventional positive pulsed corona.

Highlights

Atmospheric pressure cold plasmas have been found of great value in the field of bio-engineering, medicine, food processing, etc. due to its ability to produce reactive gas species and radicals with minimal energy consumption and gas heating
A stainless-steel sewing needle with a tip diameter of approximately 200 μm that was fixed onto the end of a high voltage (HV) cable was utilized as the HV central electrode
It is important to note that only positive pulsed corona discharges were studied in this work, while Trichel pulses associated with negative polarity voltage at pin electrode are not considered in this work

Summary

Introduction

Atmospheric pressure cold plasmas have been found of great value in the field of bio-engineering, medicine, food processing, etc. due to its ability to produce reactive gas species and radicals with minimal energy consumption and gas heating. Conventional atmospheric pressure cold plasmas are generated in noble gas, nitrogen, or air by alternating or pulsed HV powers, with a heating of gas by usually less than 50K while electron temperature can be 1-10 eV. Corona discharge is a very widely used method to produce atmospheric pressure cold plasmas. It’s been shown to have a great value in the industry for decontamination, pollution control, etc. It is applicable in flow control over airfoil for being able to increase lift, delay separation, etc. In addition, DC corona discharge devices have been miniaturized for various kinds of applications such as air particle monitoring, removing airborne bacteria in respirator, bacteria lysis cartridge for water-borne pathogen detection system, etc. Atmospheric pressure cold plasmas have been found of great value in the field of bio-engineering, medicine, food processing, etc. Conventional atmospheric pressure cold plasmas are generated in noble gas, nitrogen, or air by alternating or pulsed HV powers, with a heating of gas by usually less than 50K while electron temperature can be 1-10 eV.. Corona discharge is a very widely used method to produce atmospheric pressure cold plasmas.. It’s been shown to have a great value in the industry for decontamination, pollution control, etc.. It’s been shown to have a great value in the industry for decontamination, pollution control, etc.6 It is applicable in flow control over airfoil for being able to increase lift, delay separation, etc.. Negative corona discharge was utilized for a pressure sensor and a flow velocity meter.

Methods

Results

Conclusion