Investigation into the thermal effect of the LIPS-200 ion thruster plume

The distribution of the thermal effects of the ion thruster plume are essential for estimating the influence of the thruster plume, improving the layout of the spacecraft, and for the thermal shielding of critical sensitive components. In order to obtain the heat flow distribution in the plume of the LIPS-200 xenon ion thruster, an experimental study of the thermal effects of the plume has been conducted in this work,with a total heat flow sensor and a radiant heat flow sensor over an axial distance of 0.5–0.9 m and a thruster angle of 0°–60°. Combined with a Faraday probe and a retarding potential analyzer, the thermal accommodation coefficient of the sensor surface in the plume is available. The results of the experiment show that the xenon ion thruster plume heat flow is mainly concentrated within a range of15°. The total and radial heat flow of the plume downstream of the thruster gradually decreases along the axial and radial directions, with the corresponding values of 11.78 k W m^(-2) and 0.3 k W m^(-2) for the axial 0.5 m position, respectively. At the same position, the radiation heat flow accounts for a very small part of the total heat flow, approximately 3%–5%. The thermal accommodation factor is0.72–0.99 over the measured region. Furthermore, the PIC and DSMC methods based on the Maxwell thermal accommodation coefficient model(EX-PWS) show a maximum error of 28.6% between simulation and experiment for LIPS-200 ion thruster plume heat flow, which, on the one hand, provides an experimental basis for studying the interaction between the ion thruster and the spacecraft, and on the other hand provides optimization of the ion thruster plume simulation model.

LIPS-100离子推力器挡板通道面积优化研究

发散场离子推力器挡板通道面积显著影响进入放电室的原初电子能量和密度分布,因此成为影响放电室性能的关键因素之一。为了提高放电稳定性、降低阳极电压和放电功耗,在理论模型指导下,利用试验手段开展了LIPS-100离子推力器挡板通道面积的优化,通过对不同挡板直径和阴极极靴直径的组合试验,获得了优化的挡板通道面积,其值比优化前减小约19%。优化后的试验结果表明,在1~20 mN宽范围工作过程中,阳极电压基本保持在38 V以下,降低了约4 V;阳极电压振荡值降低约一半,在6~15 V之间;20 mN额定工况下的放电功率降低10 W左右。阳极电压降低使得计算分析的推力器屏栅极寿命比优化前提高了50%以上。

Analysis of Numerical Simulation Results of LIPS-200 Lifetime Experiments

Accelerator grid structural and electron backstreaming failures are the most important factors affecting the ion thruster＇s lifetime.During the thruster＇s operation,Charge Exchange Xenon（CEX） ions are generated from collisions between plasma and neutral atoms.Those CEX ions grid＇s barrel and wall frequently,which cause the failures of the grid system.In order to validate whether the 20 cm Lanzhou Ion Propulsion System（LIPS-200） satisfies China＇s communication satellite platform＇s application requirement for North-South Station Keeping（NSSK）,this study analyzed the measured depth of the pit/groove on the accelerator grid＇s wall and aperture diameter＇s variation and estimated the operating lifetime of the ion thruster.Different from the previous method,in this paper,the experimental results after the 5500 h of accumulated operation of the LIPS-200 ion thruster are presented firstly.Then,based on these results,theoretical analysis and numerical calculations were firstly performed to predict the on-orbit lifetime of LIPS-200.The results obtained were more accurate to calculate the reliability and analyze the failure modes of the ion thruster.The results indicated that the predicted lifetime of LIPS-200＇s was about 13218.1 h which could satisfy the required lifetime requirement of 11000 h very well.

卫星敏感区域霍尔推力器束流沉积污染模型

安装在卫星上的霍尔推力器工作时喷出的高速束流会对卫星太阳电池阵列产生溅射,卫星太阳电池阵列溅射产物返回至卫星敏感区对敏感设备产生沉积污染。本文建立了兰州空间技术物理研究所LHT-100霍尔推力器的束流模型,应用LHT-100霍尔推力器束流模型计算了霍尔推力器的束流分布和束流发散半角。并结合该束流模型建立了卫星敏感区沉积模型,计算了安装在卫星上的LHT-100霍尔推力器束流在卫星敏感区域的沉积率,对敏感器在卫星上的安装布局提供重要的理论指导,同时也为LHT-100霍尔推力器在卫星上的安装倾角提供理论依据。