Cylindrical electrodes for neutralization of insulating flowing particles

Abstract

This paper is aimed at studying charge neutralization of flowing particles using a DC corona discharge. The efficiency of two electrodes configurations, namely cone-grid and coaxial cylinder, was experimentally studied. The influence of electrode placement in the middle or at the end of a lab-scale canalization installation is highlighted. Surface potential distribution and charge measurements showed that both configurations can lead to excellent neutralization rates, of around 99%, depending on electrode voltage and placement. The performances of the cone-grid configuration were found to vary according to the electrode placement. Conversely, the coaxial configuration is more stable and, practically, placement independent. A theoretical calculation of required corona discharge to perfectly neutralize charges is also presented. The obtained formula was experimentally verified showing a good agreement between calculation and measurement. Furthermore, the influence of charged particles on the corona discharge when crossing the coaxial electrode is highlighted through discharge current measurement and electric field calculation using finite element software. The charged particles were found to alter the electric field distribution and discharge current resulting in the electric field increase near the wire and his decrease near the grounded cylinder. Therefore, the charged particles act as a dielectric barrier that can affect the discharge current.