Mechanism of Thrust–Power Ratio Improvement Using Plasma Actuator with Discretized Encapsulated Electrodes

Abstract

Plasma actuators (PA) can be utilized as fluid control devices without moving parts, but further improvement in drive efficiency is necessary. Herein, string-type PAs with up to 12 insulated conductive wires were evaluated to replace sheet-type PAs having a single encapsulated electrode. The thrust–power ratio of string-type PAs with eight or more wires is nine times that of a single-wire PA. This is due to the substantial increase in the width of the encapsulated electrode and the discrete arrangement of conductors in the streamwise direction. To determine the factors influencing the performance of PAs with discrete encapsulated electrodes, sheet-type PAs with and without discretized encapsulated electrodes and with the same configuration as string-type PAs were characterized. The measurement results revealed that no significant difference exists in the plasma extension length (LDBD) between sheet-type PAs without and with discretization under the same applied voltage, but 25% and 45% decreases in the thrust and power consumption, respectively, were observed compared to those of string-type PAs. The discretization of the encapsulated electrodes in the sheet-type plasma actuator increased the thrust–power ratio by 30%. Efficient non-mechanical fluid control using dielectric barrier discharge is therefore possible with string-type PAs with discrete electrodes.