Influence of the energy dissipation rate in the discharge of a plasma synthetic jet actuator

Abstract

Abstract.A promising actuator for high-speed flow control, referred to as a Plasma Synthetic Jet (P.S.J), is being studied by the DMAE department of the ONERA, and the Laplace laboratory of the CNRS, in France. This actuator was inspired by the "Sparkjet" device developed by the Johns Hopkins University Applied Physics Laboratory. The PSJ, which produces a synthetic jet with high exhaust velocities, no active mechanical components and no mass flow admission, holds the promise of enabling high-speed flows to be manipulated. With this high velocity jet it is possible to reduce fluid phenomena such as transition and turbulence, thus making it possible to increase an aircraft's performance whilst at the same time reducing its environmental impact. A thermal plasma discharge was created in a micro cavity, causing the gas to be expelled. It is relevant that the velocity and momentum depend on the energy dispersed by the electric discharge. To control the frequency and energy dispersed in the plasma, the Laplace laboratory has developed two high voltage power supply systems. These allow two different types of discharge to be produced, with energy being supplied to the discharge in two different manners. In this paper, we focus on the impact of the power supply on the Plasma Synthetic Jet, and in particular on the role of the rate of energy dissipation in the discharge. In order to estimate the influence of the power supply on the machinery of the actuator, specific experimental techniques were used to investigate the electrical (voltage, current), thermal (Infra-red camera) and aerodynamic (jet duration, isentropic pressure, jet velocity) characteristics. These data sets were used to determine which of the two power supplies was more effective, thus allowing us to reach several conclusions concerning the importance of the energy dissipation rate on the PSJ actuator.1.

Characterisation of plasma synthetic jet actuators in quiescent flow

“…Commonly adopted discharge types consist of capacitive discharge, inductive discharge, nanosecond pulse discharge, and pulsed DC discharge. Jets induced by the capacitive discharge demonstrate higher peak jet velocity but shorter jet duration [26] compared with inductive discharge type. By comparing the experimental pulsed thrust with that obtained from analytical models, heating efficiency of the capacitive discharge has been determined to be less than 10%, and inversely proportional to the amount of energy deposition [27][28][29].…”

Effect of slotted exit orifice on performance of plasma synthetic jet actuator

“…Following an increasing energy level criterion, commonly used discharge types can be classified into nanosecond-pulsed discharge, pulsed DC discharge and capacitive discharge (Zong et al 2015;Zhu et al 2015;Shin 2010;Reedy et al 2013;Belinger et al 2011). Nanosecond-pulsed discharge merits from a high heating efficiency (>40%), however can only be used to feed small-volume PSJA (tens of mm 3 ), due to the low discharge energy available from standard nanosecond pulses (<20 mJ) (Zhu et al 2015;Xu et al 2014).…”

Interaction between plasma synthetic jet and subsonic turbulent boundary layer

“…A morphological deviation from conventional synthetic jets is the absence of any moving components. Nanosecond pulse discharge (Zong et al 2015), pulsed DC discharge (Shin 2010) and capacitive discharge (Belinger et al 2011) can be utilized to rapidly pressurize the cavity gas, depending on the cavity volume. Narayanaswamy, Raja & Clemens (2010) investigated a small-cavity PSJA (~22 mm 3 ) fed by the pulsed DC discharge (discharge energy: 30 mJ).…”