DC-driven positive streamer coronas in airflow

TL;DR

This study investigates how laminar airflow influences positive streamer coronas in a needle-to-plate setup, revealing that wind speed affects discharge properties, propagation direction, and pulsation behavior.

Contribution

It provides detailed experimental analysis of airflow effects on streamer corona characteristics, including statistical properties and propagation directions, in a controlled wind tunnel environment.

Findings

Increased wind speed leads to greater dispersion of discharge parameters.

Mean inter-pulse period decreases and pulsation frequency increases with wind speed.

Streamer propagation direction shifts with wind speed, favoring upwind at higher velocities.

Abstract

An experimental study of the effect of laminar airflow on positive self-pulsating streamer coronas in a needle-to-plate geometry is presented. The experiments are performed in an open return wind tunnel with winds up to 30 m/s orthogonal to the needle. The experimental data is presented in terms of statistical properties of the discharge, inferred from high resolution, large sample-size current waveforms. The key properties of the current pulsations, namely inter-pulse period, peak current, deposited energy, and pulse width are analyzed as a function of wind speed and applied DC voltage. All parameters increase in dispersion with wind speed. The mean of the inter-pulse period decreases with wind speed and the mean pulsation frequency increases. The peak currents and energies per pulsation have a general tendency to decrease in magnitude but also higher-current, higher-energy, streamer bursts are observed. At low wind speeds, streamers preferentially propagate in the downwind direction but, as the wind speed is increased, more streamers can propagate upwind. Synchronized imaging reveals correlations between the streamer direction and the electrical characteristics.