Discharge Characteristics of Ring-Type Flow-Stabilized Pulsed Corona Discharge Radical Shower Systems

The discharge characteristics of a ring-type flow-stabilized pulsed corona discharge radical shower system (RCDRS) were investigated. An RCDRS with six hollow electrodes was studied. A low dc voltage charging of an ignition coil-type power supply was used to generate a pulse high voltage. Experiments were conducted for an applied charging dc voltage from 5 V to 18 V, a pulse repetition rate from 50 Hz to 200 Hz, and an injected air flow rate from 2.5 to 4.6 L/min per hollow electrode. The discharge characteristics were measured using current and voltage probes, and the morphology of the discharge was observed using a CCD camera. The pulsed waveforms of current, voltage, and power (secondary side output) were studied in terms of the input power (primary side), as well as the current and voltage, with the observed optical images for optimization. The results show that the maximum discharge current, voltage, and power increase with increasing primary side dc voltage or power. The pulse repetition rate affected the maximum discharge characteristics in terms of the primary side dc voltage, while the air flow rate did not. The maximum volume averaged plasma density is on the order of $10^{11}\ \hbox{ions/cm}^{3}$ for the 10-cm diameter and 5-cm-long flow channel volume.