Plasma Flow Structure of Direct-Current Arcjet Thrusters and Its Spacecraft Interaction Research

直流电弧喷射推进器等离子流结构及其与航天器相互作用研究

基本信息

批准号：
13450398
负责人：
TAHARA Hirokazu
金额：
$ 8.45万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

Spectroscopic and electrostatic probe measurements were made to examine plasma characteristics with or without a titanium plate for a 10-kW-class direct-current arcjet thruster. Heat fluxes into the plate from the plasma were also evaluated with a Nickel slug and thermocouple arrangement. Ammonia and mixtures of nitrogen and hydrogen were used as a working gas. The NH_3 and N\2+3H_2 plasmas in the nozzle and in the downstream plume without a substrate plate were in thermodynamical nonequilibrium states. As a result, the H-atom electronic excitation temperature and the N_2 molecule-rotational excitation temperature intensively decreased downstream in the nozzle although the NH molecule-rotational excitation temperature did not show an axial decrease. Each temperature was kept in a small range in the plume without a substrate plate except for the NH rotational temperature for NH_3 working gas. On the other hand, as approaching the titanium plate, the thermodynamical nonequilibrium plasma came to be a temperature-equilibrium one because the plasma flow tended to stagnate in front of the plate. The electron temperature had a small radial variation near the plate. Both the electron number density and the heat flux decreased radially outward, and an increase in H_2 mole fraction raised them at a constant radial position. In cases with NH_3 and N_2+3H_2, a radical of NH with a radially wide distribution was considered to contribute to the better nitriding as a chemically active and non heating process.

进行了光谱和静电探针测量，以检查有或没有钛板的血浆特性，用于10 kW级的直流电流推进器。还通过镍弹和热电偶排列评估了从血浆中进入板的热通量。氮和氢的氨和混合物用作工作气体。喷嘴中的NH_3和N \ 2+2+3H_2等离子体在没有底物板的情况下以热力学非平衡状态处。结果，尽管NH分子 - 旋转激发温度没有显示出轴向降低，但在喷嘴中的H原子电子激发温度和N_2分子激发温度强烈降低。除了NH_3工作气体的NH旋转温度外，每个温度都保持在没有基板板的羽流中。另一方面，随着接近钛板的接近，热力学非平衡等离子体成为温度平衡的血浆，因为血浆流量倾向于停滞在板前。电子温度在板附近的径向变化很小。电子数密度和热通量都在径向向外降低，而H_2摩尔分数的增加使它们在恒定的径向位置上升高。在使用NH_3和N_2+3H_2的情况下，具有径向宽分布的NH的自由基被认为有助于更好的硝化作用作为化学活性和非加热过程。