Evaluation of Back-Pressure Effect on Thrust Measurement

背压对推力测量影响的评估

• 批准号: 07044139
• 负责人: KOMURASAKI Kimiya
• 金额: $ 0.96万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 无数据
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07044139/
• 关键词: Hall Thruter; Electric Propulsion; Thrust Performance

Electric propulsion device must be tested in a vacuum chamber for simulating the space environment. In order to evaluate the back-pressure effect on thrust measurement in a simulation chamber, we bring our Hall thruster, which is one of electrostatic accelerators, to the university of Michigan for testing in a good vacuum condition.The department of Aerospace engineering of the university of Michigan has a huge vacuum facility (6 m - diameter, 9 m -long, 180,000 litter/s pumping speed, ) which can produce one order higher vacuum environment than our facility at Nagoya university (1 m diameter, 2 m - long, 8000 litter/s pumping speed.)The discharge characteristics recorded in the big chamber was almost same as that recorded in a small chamber in Japan. Therefore, it can be concluded that the back-pressure hardly affect the discharge inside the thruster.The measured total beam-current is exponentially decreased according to the distance from the thruster exit. This tendency is well explained by theoretical prediction depending on the mean free path for charge exchange reactions between beam ions and ambient neutral particles. This result shows that the total beam-current can be estimated even in a relatively low vacuum if the effect of charge exchange reactions is taken into account.Two dimensional plasma potential distribution shows the valley of potential around the cathode. The diameter of the valley is approximately one meter. It indicates that the chamber-wall effect can arise in a vacuum chamber whose diameter is less than one meter.Thrust was measured using the thrust stand made by electric propulsion laboratory of the university of Michigan. However, the thrust level of our thruster was to low to be measured with high accuracy. Therefore, we failed to have a thruster performance directly from the thrust measurement. The performance is calculated from measured total beam-current, mean ion velocity, and divergence angle.

电推进装置必须在模拟空间环境的真空室中进行试验。为了在模拟室中评估背压对推力测量的影响，我们将静电加速器之一的霍尔推力器带到密歇根大学进行测试，在良好的真空条件下进行测试。密歇根大学航空航天工程系拥有巨大的真空设备（直径6米，长9米，抽速180，000升/秒），该装置比我们在名古屋大学的装置（直径1米，长2米，抽速8000升/秒）高一个数量级。在大室中记录到的放电特性与在日本的小室中记录到的放电特性几乎相同。因此，反压对推力器内的放电几乎没有影响，测得的总束流随离推力器出口距离的增加呈指数衰减。这种趋势很好地解释了理论预测取决于束离子和周围的中性粒子之间的电荷交换反应的平均自由程。结果表明，在考虑电荷交换反应的情况下，即使在较低的真空度下，也可以估算出总束流，二维等离子体电位分布显示了阴极附近的电位谷。山谷的直径大约一米。利用美国密歇根大学电推进实验室研制的推力试验台测量了推力。然而，我们的推进器的推力水平太低，无法进行高精度测量。因此，我们无法直接从推力测量中获得推力器性能。的性能计算从测量的总束流，平均离子速度，和发散角。

项目成果

Kenji Mikami, Kimiya Komurasaki and Toshi, Fujiwara: "Channel configuration and thrust performance of Hall thruster" Journal of Japanese society for aeronautical and space science. preparing for submission.

Kenji Mikami、Kimiya Komurasaki 和 Toshi, Fujiwara：“霍尔推进器的通道配置和推力性能”日本航空航天学会杂志。

三上建治,小紫公也,藤原俊隆: "ホール型スラスタの放電チャンネル形状と推進性能" 日本航空宇宙学会誌. (投稿準備中).

Kenji Mikami、Kimiya Komurasaki、Toshitaka Fujiwara：“霍尔式推进器的放电通道形状和推进性能”日本航空学会学报（准备投稿）。