离子液体电喷推力器羽流中和特性研究

Plume Neutralization Characteristics of Ionic Liquid Electrospray Thruster

关键词:  离子液体电喷推力器  羽流  自中和  时间变化法  空间变化法

Key words:  Ionic liquid electrospray thruster  Plume  Self-neutralization  Time-varying method  Spatial-varying method

摘要:

电推进装置的带电羽流会对航天器产生多种危害，为了降低离子液体电喷推力器带电羽流对航天器产生的潜在安全风险，需要对其进行羽流中和。根据离子液体电喷推力器的羽流自中和特性，提出了时间变化法和空间变化法，并对其进行了实验验证。用时间变化法分析了单推力器的脉冲电压的频率、幅值和占空比对羽流中和特性的影响。以20Hz作为实验的条件，单推力器样机实现羽流中和的正负电压幅值比为0.95~0.98，在发射电压幅值分别为±2.2，±2.6，±3.0kV情况下，羽流中和时正电压占空比分别为35.5%，38.1%，40.4%。空间变化法中使用双推力器模块分析了电压幅值对羽流中和特性的影响。实验结果表明，两个推力器模块羽流中和时的正负电压幅值比为0.95~0.98，与时间变化法的实验结果基本一致，证明了两个推力器协同工作情况下羽流中和的可行性。

Abstract:

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.