Plasma Micro-Thrusters for Micro-Aerial Vehicles

The present paper investigates the effectiveness of dielectric barrier discharge plasma actuators for use as micro thrusters in micro and nano aerial vehicles (μAVs and nAVs). For these small scale vehicles, the range of Re is very small and the subsequent aerodynamics are in a region of relatively unknown physics. Development of suitable propulsion systems involve the integration of a reliable power source with sufficient energy and power density to carry out a mission. The propulsion system must be capable of demonstrating highly efficient conversion of stored energy to thrust to propel the vehicle in both hover and forward flight. Thus, highly efficient actuators are required for micro and nano air vehicle designs. This configuration consists of a closed circumferential arrangement which yields a body force when a voltage difference is applied across the inner and outer electrodes. The primary flow is driven by this zero-net mass flux jet at the wall that then entrains fluid in the core of the duct. This also results in a unique configuration for studying impulsively started jet phenomena. To determine optimum thrust generation, thrusters of various sizes and aspect ratios have been investigated along with pulsing the actuator input. Measurements are made using PIV and the effects of these parameters on the induced velocity and resulting thrust are then presented. The values of the induced velocities increase with the forcing frequency and duty cycle although there is a peak value for the forcing frequency after which the velocity and thrust decrease. The influence of the length-to-diameter (l/di) ratio is also significant; the velocities and thrust increase as the inner diameter of the tubes are increased. Preliminary conclusions are that this circumferential arrangement of the plasma actuator can be used as a micro thruster. Configurations for use in micro and nano aerial vehicles will be presented.