离子液体电喷推力器羽流中和特性研究

The charged plumes of electric propulsion devices are commonly responsible for many kinds of hazards to a spacecraft. It is essential to neutralize the charged plume of ionic liquid electrospray thruster to reduce such potential safety hazards. In line with the characteristics of plume self-neutralization of ionic liquid electrospray thruster, two methods of plume neutralization were put forward in this paper: time-varying method and spatial-varying method. They were both verified by experiments discussed in the paper. The effects of frequency, amplitude and duty ratio of pulse voltage on the neutralization characteristics of a single thruster were analyzed by time-varying method. In this study, frequency of 20Hz was used as the experimental condition. The positive to negative voltage amplitude ratio of a single thruster prototype to realize plume neutralization was between 0.95 and 0.98. The duty cycles of positive voltage were 35.5%, 38.1% and 40.4% for emission voltage amplitudes of ±2.2kV, ±2.6kV and ±3.0kV, respectively. The effects of voltage amplitude on the characteristics of plume neutralization were analyzed by using a dual thruster module in the spatial-varying method. The experimental results have shown that the amplitude ratio of positive and negative voltage is between 0.95 and 0.98, which is basically consistent with the experimental results of time-varying method, proving the feasibility of plume neutralization under the condition of two thrusters working together.