高温超导磁悬浮微小推力测量的悬浮摩擦损耗特性研究

This proposal is a cross subject combined with microthrust measurement and high temperature superconducting magnetic levitation (HTSM), which plans to investigate and solve the levitation friction loss problem of HTSM used in microthrust measurement for electric thrusters. In order to avoid interferences caused by propellant and power supplying process of traditional microthrust measurements and increase testing precision, the superconducting magnetic levitation is used in the microthrust measurement to achieve a fully suspended measuring method which can make the total thruster system work in the levitation state, get rid of all connecting interferences, and directly get the effect of the thrust and impulse momentum. Here the levitation friction loss is mainly studied as the most important problem. Relative theoretical models are concluded and created based on Bean critical state model, and an effective numerical simulation method is developed to calculate the friction loss. We design and establish a set of single permanent magnet /superconductor levitation testing setup and a set of rotating weighted suspension system to measure the friction loss characteristics in quasi-static and dynamic states, and then study relative loss factors and rules. Cogging torque features happened in the low frequency rotation are also investigated and the application method of the copping torque is given. The research is crucial to understand the friction loss mechanism and properties of HTSM under tiny disturbance. It will provide important theoretical basis and the technical support for developing the microthrust measuring device with higher precision.

本项目是结合微小推力测量和高温超导磁悬浮等不同研究领域的交叉性课题，拟解决高温超导磁悬浮应用于电推力器微小推力测量环境的悬浮摩擦损耗问题。针对传统微小推力测量难以根本解决推进剂、电力供应造成的力干扰和测量精度较低的问题，提出将超导磁悬浮应用于微小推力测量中，实现一种全推进系统悬浮工作、无连接干扰、可以直接测量和评估推力器冲量作用效果的悬浮式推力测量方法。针对最为核心的悬浮摩擦损耗问题，基于Bean临界态模型给出描述超导悬浮摩擦损耗的理论模型，并以此为基础发展合理的超导悬浮摩擦损耗数值模拟研究方法。通过单块永磁/超导悬浮和承载型超导悬浮平台的摩擦损耗测试，研究超导悬浮微推测量准静态、动态摩擦损耗特性的影响因素及规律，明确低频旋转齿扭矩效应的特性与应用方法。该研究工作对阐明微小扰动下的超导悬浮摩擦损耗机制与特性具有重要意义，将为更高精度的微小推力测量装置开发提供重要理论依据和技术基础支撑。

作为衡量电推进等微小推力器动力特性的不可或缺手段，微小推力测量具有很大的挑战性。推力器的管线连接以及自重平衡等干扰因素会对微小推力的测量精度造成影响。因此，如何采用有效手段减少干扰、提高测试精度成为微小推力测量的首要问题。将高温超导自稳定磁悬浮技术应用于微小推力测量中，使全推进系统处于悬浮工作状态，实现一种可以直接测量和评估推力器冲量作用效果的磁悬浮旋转式微小推力测量方法，有望彻底消除推力器自重、推进剂及电力供应过程中产生的干扰，从而大大提高推力器的地面实验测试水平。本项目基于高温超导体的交流损耗特性，开展了高温超导磁悬浮结构应用于微小推力测量台架的应用性基础研究。针对悬浮摩擦损耗这一核心问题，通过试验分析和数值仿真重点研究了各影响因素对其影响的相关规律。实验研究精确给出了摩擦损耗随场冷高度以及初始激励动量变化的规律，分析了超导体温度与场冷高度对摩擦损耗影响规律。通过研究超导块材的各向异性对摩擦损耗的影响，实验发现存在永磁转子最优位置和姿态使得摩擦损耗最小。基于Bean和Kim模型建立了描述涡流损耗和磁滞损耗的数学模型，并验证了该计算模型的合理性，开展了稳态运行环境下的单块超导悬浮摩擦损耗数值模拟研究，计算了稳态下单块超导-永磁悬浮低频转动的损耗，对摩擦损耗的电磁和动力学特性提供了一定的物理过程解释。目前该基金属于国家自然科学面上基金项目，已发表学术论文9篇，其中SCI收录5篇，授权国家发明专利1项。本项目的研究不仅丰富了高温超导体电磁力学特性的基础研究内容，而且拓宽了高温超导磁悬浮出交通运输、电磁发射和飞轮储能之外的新领域。项目成果对阐明微小扰动下的超导悬浮摩擦损耗机制与特性具有重要意义，将为更高精度的微小推力测量装置开发提供重要理论依据和技术基础支撑。