Thermal effect on the performance of an alternating-current dielectric-barrier-discharge plasma actuator

Abstract

The dielectric-barrier-discharge (DBD) plasma actuator is a popular technology for active flow control; however, the influence of the heat generated by the actuator on its performance is seldom mentioned. In this work, an experimental investigation is conducted to evaluate the interaction between spontaneous heat generation and the performance of an alternating-current DBD (AC-DBD) plasma actuator. The characteristics of the AC-DBD plasma actuator are examined temporally in quiescent air, including the profile of the induced flow, capacitance properties, power consumption, plasma light emission, and surface temperature. The particle image velocimetry shows that the velocity profile of the induced flow increases temporally, indicating enhanced momentum injection by the AC-DBD plasma actuator. The capacitance, power consumption, plasma brightness, and surface temperature increase with the operation time analogously to exponential curves (f (x)=a-bexp-cx), and the values of these properties are proportional to 3.5 power of the applied voltage. The dielectric surface is categorized into three typical streamwise regions according to the heat generation characteristics: The plasma region, the insulated electrode region, and the far-field region. The dominant heat generation occurs in the plasma region due to the plasma discharge. The temperature increase of the local dielectric and the gas-plasma mixture enlarges the actuator capacitance, benefits the local induced electric field, and results in longer mean free paths of particles and stronger discharges accordingly. Thus, the spontaneous heat generation affects the induced ionic wind, and the performance of the AC-DBD plasma actuator is time dependent during the early period of the operation.