Influence of humidity and air pressure on thrust characteristics of ion wind propulsion systems

Ion wind propulsion systems have potential applications in the field of unmanned aerial vehicle (UAV) due to their compactness, quiet operation, and simple design. Previous studies have focused on the influences of power source, electrode arrangement, size, and shape on the output thrust characteristics. However, few studies have been performed on the environmental conditions, which can be beneficial for the practical applications of ion wind aircraft in various climatic conditions. In this work, a measurement platform of the output characteristics of ion wind propulsion system under various environmental conditions has been established. The experimental pressure range is 1 to 0.7 atm, and the relative humidity (RH) is 30% to 92%. The effects of air pressure and humidity, and voltage level on the thrust, thrust-to-power radio (TPR) corona current have been investigated. The results show that the corona current and thrust of the wire-wing electrode array decrease with RH within the range of 30% to 80%. Under higher humidity, the corona current and thrust tend to increase at most voltage levels. Moreover, the thrust and current both decrease with reduced pressure when keeping the voltage-to-pressure ratio (U/P) unchanged. It was also found that the thrust is roughly proportional to the square of the pressure. Finally, the possible explanations of the coupled influences on the output characteristics were discussed.