Numerical Study on Performance Improvement Mechanism of Tri-Electrode Plasma Actuator

Abstract

Tri-electrode plasma actuator (TED-PA), which has a third electrode with high DC voltage, can generate stronger jet than that of conventional two-electrode type plasma actuator. However, the behavior of the jet in TED-PA is unexpected; the induced jet is deflected upward. To clarify the jet deflection mechanism and performance improvement mechanism of TED-PA, discharge plasma and flow field is numerically simulated based on the three-fluid plasma model and the incompressible Navier-Stokes equations with the body force term, respectively. The results show the jet deflection appears in both cases of negative and positive DC voltage; a rightward jet from the AC electrode and a leftward jet from the DC electrode are generated and the collision of the two jets generate the upward jet. The jet becomes stronger by the DC electrode due to two factors; the negative body force generation around the DC electrode and the positive body force enhancement around the AC electrode. The negative force generation around the DC electrode results from the drift motion of the positive ions in the positive DC voltage case, and on the other hand, that of the negative ions in the negative DC voltage case. The positive force enhancement around the AC electrode is due to the electric field intensification by the DC voltage.