Current, thrust, and power of a corona discharge plasma thruster at tropospheric altitude

Abstract Recent developments in electro-aerodynamics (EAD) thrusters that use plasma have demonstrated their abilities for aircraft propulsion, at least for low-velocity drones. Further improvements in the technology bring EAD propulsion closer to full-scale applications. However, certain doubts still exist concerning their behavior in different atmospheric conditions. The study focuses on the effects of altitude on the propulsive performance of a corona discharge thruster in the troposphere. A thruster is placed in a climatic chamber that can vary the temperature and pressure independently, and force and current measurements provide the thrust generation and power consumption of the thruster. First, tests under varying pressure between 500 and 1000 hPa were performed at room temperature. As expected, at constant voltage, they highlight that the power increases almost linearly when the pressure decreases. Conversely, they demonstrated that the thrust decreases with pressure at a constant current. The combined effects result in a loss of effectiveness (i.e. thrust-to-power ratio) when the pressure reduces. Yet, a plateau of maximum effectiveness is achieved between 800 and 1000 hPa. Secondly, the temperature was varied between −20 °C and +30 °C at ground pressure. No significant effect was captured concerning the current and power, and a weak decrease in thrust was measured at higher temperatures. Finally, altitudes between 0 and 6 km were simulated by combining pressure and temperature modifications. Mostly led by the pressure drop, the power decreases linearly when the altitude increases, but the thrust decreases to a plateau between 3 and 6 km. Hence, the effectiveness also decreases with altitude down to a stagnation between 3 and 6 km. The coupled decreases in drag and thrust with altitude engender a small decrease in the maximum achievable freestream velocity of the thruster down to a plateau over 3 km.