Numerical simulation and experimental study of the negative corona charging process on a wire-to-wire electrode in a steam jet

Abstract

This study investigated the influence of wire-to-wire electrode structures and steam conditions on corona discharge behavior and the charging characteristics of steam jets. The corona discharge current, charge-to-mass ratio of the steam jet, and droplet size distribution near the electrode were measured. The temperature and velocity distributions along the central axis of the steam jet were determined using empirical formulas. A joint model of corona unipolar particles and field-induced charging along the jet axis was developed and the numerical results closely matched experimental data. The findings revealed that variations in water vapor content around the corona electrode significantly affected corona currents. Specifically, higher water vapor mass fractions resulted in reduced corona discharge currents. Particle size measurements indicated that steam jets with higher Reynolds numbers generated smaller droplets in greater quantities. Larger droplets moving in the steam jet accumulated higher charges, but the charge-to-mass ratio decreases with increasing droplet size. Notably, the distribution of droplet sizes was a critical factor influencing the charging characteristics of steam jets. A steam jet with a higher Reynolds number achieved a charge-to-mass ratio of up to 2.17 mC/kg, demonstrating its enhanced charging capacity.