Static aeroelasticity of the propulsion system of ion propulsion unmanned aerial vehicles

Shuai Hao ^a,c, Tielin Ma ^b, She Chen ^d,*, Hongzhong Ma ^c, Jinwu Xiang ^a, Fangxiang Ouyang ^d

a. School of Aeronautic Science and Engineering, Beihang University, Beijing 100191, China
         b. Research Institute of Unmanned Systems, Beihang University, Beijing 100191, China
         c. Hiwing General Aviation Equipment Co., Ltd., Beijing 100074, China
         d. College of Electrical and Information Engineering, Hunan University, Changsha 410082, China

Abstract: “Ionic wind” generators are used as the main propulsion system in ion propulsion unmanned aerial vehicles (UAVs). Owing to the large size and poor stiffness of the electrode array in the propulsion system, the electrode array is prone to deformation under the flight load. In this work, the thrust characteristics and static aeroelastic properties of "ionic wind" propulsion systems were analysed in detail. The simulation model for an "ionic wind" propulsion system was estab-lished by coupling a two-dimensional gas discharge model with a gas dynamics model. The influences of electrode voltage, spacing, size, and shape on the performance of the propulsion system were investigated. The fluid-solid interaction method was used to solve static aeroelastic characteristics under deformation. The aerodynamic and thrust performances of the elastic state and the rigid state were compared. It was found that the operating voltage, the distance between two electrodes, and the emitter radius had greater impacts on the thrust of the propulsion system. The propulsion system had a small contribution to the lift but a large contribution to the drag. In the elastic state, the lift coefficient accounted for 12.2%, and the drag coeffi-cient accounted for 25.8%. Under the action of the downwash airflow from the wing, the propulsion system formed a upward moment around the center of mass, which contributed greatly to the pitching moment derivative of the whole aircraft. In the elastic state, the pitching moment derivative accounted for 29.7%. After elastic deformation, the thrust action point moved upward by 28.7 mm. Hence, the no lift pitching moment is reduced by 0.104 N·m, and the pitching moment coefficient is reduced by 0.014, causing a great impact on the longitudinal trimming of the whole aircraft.

Keywords: Ion propulsion unmanned aerial vehicle (UAV); Propulsion system; Electro-aerodynamics; Static aeroelasticity; Fluid-solid interaction

https://doi.org/10.1016/j.jppr.2023.01.001