Characterizing the pin-to-ring direct-current air corona discharge by its ultrasonic signal and ozone production

Abstract

Corona discharge is a common physical phenomenon in high-voltage electricity, air purification, ozone generation, and electrostatic printing. Most research has characterized corona discharge states by time-domain current waveform or in-situ image observation. However, few have paid attention to changes in other physical quantities representing the state of the corona process and their correlations, such as ultrasonic waves and ozone. In this study, we conducted direct current corona experiments on pin-to-ring electrodes to compare the electroacoustic response caused by changes in airflow velocity, electrode structure, tip material, curvature radius, and surface morphology. The results indicate an obvious correspondence between the ultrasound signal power (USP) in the 50–200 kHz ultrasound frequency band and the transition of the corona stage. USP and ozone production (ΔO₃) are generally positively correlated, possibly corresponding to the spatial distribution of positive ion and electron density in the ionization zone during the discharge process. This work contributes to a new perspective on understanding variable control in corona discharge processes, such as the modulation effect of sound pressure gradient on electron mobility, and is beneficial for guiding the research and development of acoustic sensors for ozone, plasma acoustic wave, electrostatic equipment pollution control, and acoustic positioning methods.