Langmuir探针测量技术在MPT羽流诊断中的应用研究

【作者】 林榕；

【导师】 毛根旺；

【作者基本信息】 西北工业大学 ， 航空宇航推进理论与工程， 2004， 硕士

【摘要】 近年来,随着对航天器推进系统性能要求的不断提高,电推进以其独有的优势引起了航天界的兴趣和重视,并越来越多的被应用到空间任务中。微波等离子推力器(MPT)是一种新型的电热型推力器,它具有效率高、比冲适中、寿命长、推力范围宽、与航天器兼容性好等优点,应用前景十分广阔。 推力器的真空羽流中存在回流、热、等离子体。等离子体是电离了的气体,它由电子、离子和中性粒子组成。等离子体中的带电粒子会对太阳能帆板、天线以及各种电子设备造成干扰,因此对航天器的适用性和可靠性有重要的影响。全面研究发动机的羽流,设计出受羽流污染影响较小或不受羽流影响的一体化星体至关重要。目前,实验对于MPT羽流的认识还远远不够,所作的理论分析工作只是限于中性气体的研究,对于电子、离子等带电粒子的研究还未起步,而事实上,用理论计算的方法对这些极为微小的粒子进行研究是相当复杂的。除了理论计算,还可用实验的手段对MPT羽流进行直接测量。 本文的研究内容主要为采用有效的实验方法对MPT羽流进行研究,得出它的一些特性,即对MPT羽流进行诊断。完成的工作主要有: 1.针对目前对MPT羽流的认识,选择了一种可行的方法对MPT羽流进行诊断。 本文采用Langmuir探针和发射探针诊断方法对MPT羽流进行诊断。 2.通过研究Langmuir探针测量技术,设计、开发了与发射探针MPT羽流诊断系统。其中包括Langmuir探针与发射探针工作电源、Langmuir探针与发射探针以及数据采集和数据处理软件。通过以锯齿波向Langmuir探针施加电压得到伏安特性曲线,并可快速处理出实验结果。 3.使用Langmuir探针与发射探针诊断系统对MPT羽流进行实验研究,进一步验证诊断系统的可行性,并对电子温度、电子数密度等参数进行初步的分析,得出的实验结果和理论计算结果比较一致,为以后的研究打下基础。更多还原

【Abstract】 With incessant requirements for high performance of spacecraft propulsion system, Electric Propulsion (EP) has become a focus of spaceflight field recently because of its particular advantages, such as high efficiency, moderate Specific Impulse, long life, well compatible with spacecraft and so on. It has a wide perspective in applicationThe plume of the engine has a key effect to its applicability and reliability because the plasma consisting electrons and ions in the plume will disturb signal of electronic equipment antenna and solar board. So it is very important to develop investigation of MPT plume in all ways to design integrative spacecraft. At present MPT plume has been studied by theoretical calculation which is far from enough because it is just involved in molecule but no electron or ion investigation has done. In fact, it is extremely complicated to research the terribly little particles by means of theoretical calculation. Research to the MPT plume can be done by experimental way except theoretical calculation.Using applicable method to study MPT plume to get some characters can be called plume diagnostics. The contents of this paper include:1. On the base of the knowledge of MPT plume, it is needed to choose an applicable method to diagnostic the plume .In this paper Langmuir probe and Emissive probe were chosen because of their excellent characters.2. Technology of Langmuir probe was studied to built the Langmuir probe and Emissive probe MPT plume diagnostics system including Langmuir probe and Emissive probe working power supply system Langmuir probe Emissive probe and data collection and analyzed system. A volt-ampere curve was gained by giving Langmuir probe a variable voltage. When needed, the result of experimental could be gained immediately by the analyzed software.3. Utilizing the Langmuir probe and Emissive probe diagnostics system built up to carry the MPT plume experiment, feasibility of this method is validated. Some characters such as electron temperature -, electron density were gained and consistent to the theoretical calculation results. The research was done as a base to the coming studies.更多还原