Design and Performance of an Electrowetting Ionic Liquid Electrospray Thruster Prototype

Porous ionic liquid electrospray thrusters are capable of meeting the propulsion requirements of micro-and nanosatellites. The liquid propellant of such a thruster is usually prefilled in the porous reservoir and emitter, then passively and uncontrollably supplied to the emitter tip, which may cause excessive propellant to submerge the emitter, thereby resulting in a short circuit of the thruster. To solve the aforementioned problems, an electrowetting ionic liquid electrospray thruster prototype is developed in this study. Electrowetting is an active control technology that can supply propellant on demand from the propellant tank to the emitter. The feasibility of electrowetting the emitter and the performance of the prototype are tested in a vacuum chamber. The results show that the porous reservoir is completely wetted by the propellant within 410 s after the electrowetting process is initiated. The prototype can work stably in the voltage range of 2300 to 2800 V, with a transmission efficiency of greater than 95%. The maximum specific impulse and thrust of this prototype are 5025 s and 13.99 μN, respectively, which are similar to the performance characteristics of passively fed prototypes. This study is of great significance for improving the controllability and robustness of ionic liquid electrospray thrusters.