Experimental Studies of Plasma Actuator Performance for Separation Control

Abstract

on airfoils 1-4 . A plasma actuator is a dielectric barrier discharge (DBD) device that can be used to selectively add momentum to fluid flow over a surface to effect flow separation. Our research program is directed at studying the potential application of plasma actuators for improving the performance and efficiency of low-pressure turbines. In this application, plasma actuators can trigger the transition between laminar and turbulent flow, thus reducing drag and leading to an increase in the turbine’s efficiency. The study reported in this paper focuses on the behavior and characteristics of the plasma actuator itself and its operation under different experimental conditions, with the goal of finding ways to improve and control the plasma actuator’s efficiency for low-pressure turbine applications. In this work, DBD plasma actuators are studied in an experimental system that allows precise control of the discharge environment. The plasma actuator is operated in a vacuum chamber and its operation monitored by an array of diagnostic techniques. Measurements of the discharge current and voltage along with time resolved imaging of the discharge utilizing an Intensified Charge-Coupled Device (ICCD) camera provide information about the discharge characteristics. A lever-style balance scale system is used for measurement of the thrust generated by the plasma actuator. A capacitor-based technique allows for power measurements, from which the efficiency (thrust/power) of plasma actuators of varying designs can be compared. A key goal of this study is to arrive at scaling laws for plasma actuator performance as a function of the operating parameters (e.g., permittivity of the dielectric, frequency and amplitude of the applied voltage, and geometry of the plasma actuator). We expect such scaling laws to be of great value in the design of more effective plasma actuators for use in low-pressure turbines.