Characteristics of repetitive discharges of plasma synthetic jet actuators

Abstract

Characteristics of plasma synthetic jet (PSJ) actuators driven by repetitive pulsed discharge have drawn much attention. In this paper, the PSJ actuator is composed of a pair of tungsten electrodes and a boron nitride cavity without a cap. The cavity has a diameter of 8 mm and volume of 400 mm'. The distance between two electrodes ranges from 1 mm to 4 mm. The PSJ actuator is excited by a homemade generator CMPC-40D, output pulse parameters of which are as follows: the maximum voltage of 30 kV, the rise time of 0.5 μs, the pulse width of 8 μs, the repetition rate ranges from 0to5 kHz. Effects of pulse repetitive frequency (PRF) and air gap spacing on the discharge characteristics of a single actuator are investigated. Experimental results show that the discharge voltage increases with the increase of the gap spacing but decreases with the increase of the PRF. During the ignition time, the discharge voltage falls to zero in a few nanoseconds and the current discharge is damped sinusoidal oscillation. We observe that the energy dissipation oscillates in time, for a total discharge energy of 2 to 9.9 mJ. The energy decreases with the increase of the PRF, but it increases with the increase of the gap spacing. Furthermore, three actuators in series connection are studied. Experimental results show that synchronous discharge could be achieved for three PSJ actuators.