烧蚀型脉冲等离子体推力器能量分配机理

The energy distribution mechanism in an ablative pulsed plasma thruster

脉冲等离子体推力器(以下简称PPT)效率低下的缺点一直为使用者所诟病,但过去对其能量分配机理的研究十分匮乏,难以为高效率PPT的设计提供参考。针对这一现状,本研究以平板式烧蚀型PPT为对象,对推力器在4种不同放电能量(能量比1:2:3:4)下工作的电压、电流和脉冲烧蚀质量进行测量,并根据测量结果估算PPT的元冲量、比冲、效率等推进性能。此外,本研究还建立了能估算PPT推进剂利用率的数值模型,并用该模型分析实验研究结果。研究结果表明,能量利用率和推进剂利用率低下同时导致PPT推力器效率低下,随着放电能量的增加,PPT的能量利用率和推力器效率上升,分别从5.07%和2.88%逐渐提高至16.46%和5.23%,但推进剂利用率反而降低,由56.8%逐渐降低至31.8%。

Pulsed plasma thrusters(PPTs)have been criticized for their low efficiency over long time periods.However,few studies were about the PPT energy distribution mechanism which is very important for providing references for the designs of high-performance PPTs.In this paper,a parallel-plate ablative pulsed plasma thruster was studied.The voltage,current and ablated mass of the PPT were measured under four different discharge energies.The propulsion performance of the PPT was estimated by the experimental data.In addition,a numerical model was established and used to calculate propellant utilization of a PPT.The results show that the low efficiency of PPTs comes form their low energy utilization and low propellant utilization.As the discharge energy increases,the PPT efficiency and energy utilization increase from 5.07%to 16.5%and from 2.88%to 5.23%,respectively.However,the propellant utilization decreases from 56.8%to 31.8%as the discharge energy increases.