Enhancement of DC-driven flashing corona by dielectric enclosure

TL;DR

This study demonstrates that enclosing a high-voltage electrode in Teflon significantly broadens the stable flashing corona operating range, increases pulsing frequency and power deposition, and produces ozone-rich gases.

Contribution

Introducing a Teflon dielectric enclosure around the electrode enhances the stability, power, and frequency of flashing corona discharges compared to open-air conditions.

Findings

Expanded voltage range for stable corona from 200 V to 3-5 kV

Increased pulsing frequency up to 12 kHz

Enhanced power deposition from 10 to 220 mW

Abstract

In this work, the effect of flashing 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 flashing 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 flashing corona were tested to be mostly ozone with traceable amount of NO$_2$. The discharge used about 150 eV and 1950 eV per one ozone molecule and nitrogen dioxide molecule respectively.