Computational modeling of electric discharge inside electric propulsion systems by a hybrid PIC-MCC/FVM approach

采用混合 PIC-MCC/FVM 方法对电力推进系统内的放电进行计算建模

• 批准号: 392356807
• 负责人: Professor Dr.-Ing. Rodion Groll
• 金额: --
• 依托单位: Zentrum für angewandte Raumfahrttechnologie und Mikrogravitation (ZARM)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/392356807?language=en
• 关键词: Computational; modeling; electric; discharge; inside

Goal of the present research project is the development of a new modeling concept for plasma flows and its use for the numerical study of an arcjet thruster. This type of electric propulsion system for spacecraft enables the generation of a small and precise thrust which is in turn of vital importance for the attitude control of miniaturised satellites and for the envisioned formation flight of future satellites. The knowledge gained from the project will improve the understanding of complex plasma phenomena, such as the experimentally observed increase of electron mobility in Hall thrusters.One of the main disadvantages of the continuum-based modeling of plasma phenomena in electric propulsion systems is the necessary estimation of several physical quantities such as electric conductivity, anode temperature and transport coefficients. This estimation is often based on empiric approaches, which mainly results from the high complexity of plasma phenomena. Furthermore, full kinetic approaches, which generally avoid the estimation of transport coefficients, often exhibit prohibitively high computational requirements. In the present research project, an approach based on a hybrid model with manageable computational requirements will be pursued. To this end, charge carriers are modeled with a kinetic (PIC) approach and the neutral gas in the plasma is handled as a fluid. The results of the fluid equations are used to produce a cloud of neutral particles, which interact with the kinetic modeled electrons. Ionization and recombination rates are determined based on the kinetically obtained results and are incorporated as source terms in the fluid equations for the neutral gas. Some of the challenges regarding the description and numerical modeling of plasma phenomena in electric propulsion systems are the determination of the electric conductivity in the nozzle of an arcjet thruster without using empirical models.a nd the development of computationally efficient approaches for technical applications in which large differences of time and length scales of the physical processes exist.The main goal of the present research project is the investigation of a numerical, hybrid model that allows the accurate description of the plasma phenomena inside an electric propulsion system. In the first phase of the project, the model will be developed and validated focused on the ionization and plasma behavior inside arc jet thrusters. After conclusion of the project, a PIC-MCC/FVM-Model is available. The developed model is based on a kinetic description of electrons and enables the determination of important plasma and ionization parameters at a kinetic level.

当前研究项目的目标是开发一种新的等离子流建模概念，并将其用于电弧喷射推进器的数值研究。这种航天器电力推进系统能够产生小而精确的推力，这对于小型卫星的姿态控制和未来卫星的编队飞行至关重要。从该项目中获得的知识将提高对复杂等离子体现象的理解，例如实验观察到的霍尔推进器中电子迁移率的增加。电力推进系统中等离子体现象的基于连续介质的建模的主要缺点之一是必要的估计电导率、阳极温度和传输系数等几个物理量。这种估计通常基于经验方法，这主要是由于等离子体现象的高度复杂性造成的。此外，全动力学方法通常避免估计传输系数，通常表现出过高的计算要求。在当前的研究项目中，将寻求一种基于具有可管理计算要求的混合模型的方法。为此，采用动力学 (PIC) 方法对载流子进行建模，并将等离子体中的中性气体作为流体处理。流体方程的结果用于产生中性粒子云，这些粒子与动力学模型的电子相互作用。电离和复合速率根据动力学获得的结果确定，并作为源项纳入中性气体的流体方程中。关于电力推进系统中等离子体现象的描述和数值模拟的一些挑战是在不使用经验模型的情况下确定电弧喷射推进器喷嘴中的电导率，以及为技术应用开发计算有效的方法，其中大型物理过程的时间和长度尺度存在差异。本研究项目的主要目标是研究数值混合模型，该模型可以准确描述电力推进系统内的等离子体现象。在该项目的第一阶段，将开发和验证模型，重点关注电弧喷射推进器内的电离和等离子体行为。项目结束后，可以使用 PIC-MCC/FVM 模型。开发的模型基于电子的动力学描述，能够在动力学水平上确定重要的等离子体和电离参数。