Measurement of the charge distribution deposited by anannularplasma synthetic jet actuator over a target surface

Abstract

Annular plasma synthetic jet actuators demonstrated their ability to produce a tubular flow normal to the surface where the dielectric barrier discharge (DBD) is ignited. These fluid-dynamic actuators enhance the delivery of reactive species towards the target to be treated. In these actuators, long life charged particles are generated within the plasma region and then carried on by the induced flow. In this work, the potential distribution induced by charges deposited over an insulating target has been measured. Surface DBD actuators, made with different dielectric materials, have been supplied by different sinusoidal voltages at a constant average power supplying the discharge. Actuators with the exposed electrode connected to both the high voltage potential and grounded have been tested. The charge distribution accumulated on a target surface perpendicular to the flow has been measured at different time intervals with the plasma on. Charges advected by the flow are always positive. The potential distribution on the target surface generated by the charges has been measured. For both configurations, firstly an M-shaped distribution develops and, later on, it becomes bell-shaped. A charge build-up mechanism has been found to be faster when the exposed electrode is connected to the high voltage terminal. The target has been placed at a variable distance from 1 to 5 cm from the actuator surface. At a distance of 5 cm, induced potentials are two times smaller than those with the target at 1 cm. Measurements allow us to estimate a charge flux toward the target on the order of 1011 particles (cm2 s)−1. The results presented in this work show that the presence of charged particles in the jet flow outside the plasma could be an important factor to be accounted for when these plasma actuators are used for treatment purposes (indirect plasma treatment).

Indirect Inactivation of Candida guilliermondii by Using a Plasma Synthetic Jet Actuator: Effect of Advected Charged Particles

“…As already mentioned, the PSJA used in this work has been characterized previously. 38 In the present study, a metallic mesh positioned at a distance 1 cm from the actuator sur-tion process. All tests were carried out in open air with a relative humidity of 41 ± 5% and a temperature of 25 ± 2°C distribution of deposited charges.…”

“…etti et al 38 lower one was grounded. A metal mesh was positioned 1 cm from the actuator surface (in the "y" direction) to give the possibility to arrest free charges advected by the tubular in-A sinusoidal supply system constituted by a push-pull high-voltage transformer controlled by Arduino has been utilized to feed the discharge.…”

“…It allows to change both voltage and frequency in the range 0-20 kVp and 15-50 kHz, respectively, and can ignite the plasma with an arbitrary duty cycle. For the actuator considered in this work, eters lead to an average power supplying the plasma equal to 14 W. Electrical measurement setup is the same utilized in Neretti et al 38…”

“…PSJA sketch and metallic mesh used to arrest free charges experimental setup used in this work is the same described in Neretti et al 43 Conby using the same methodology described in Neretti et al 38 Charge distribution was evaluated from surface potential measurements by using the numerical approach described previously. 36 of C. guilliermondii serial transplants on Sabouraud dextrose agar (DIFCO) with 0.05% chloramphenicol.…”

“…34,35 Basics physics studies on linear aerodynamics plasma actuators showed the presence of charges deposited onto the actuator surface at produced within the plasma volume and subsequently advected by the tangential wall jet. 36,37 A recent experimental work 38 showed that annular actuators can also transport and deposit positive charges over a target positioned at several centimeters from the surface where the discharge is ignited. already studied both in direct and semi-indirect treatments.…”