永磁轨道上高温超导块材YBCO的悬浮稳定性数值研究

It has realistic significance that the sudty on stabilty of High-temperature Superconcting maglev.how to build the mathematical model which can describe the dynamic change between the magnetic flux and temperature in a high temperature superconductor(HTSC) is a key factor to numerical study. A mode will be built by the electromagnetic(EM) governing equations of HTSC on the basis of Maxwell's equations and the anisotropy of the resisivity,thermal diffusion equation in the HTSC combined with the magnetic-thermal constitutive relations of the HTSC.To numerically solve the governing equations, Finite Element Mothod is employed on the basis the effctive pinning center in the HTSC and the non-linear numerical treatment method of the EM governing equations have been taken into accout.Subsequently, the numerical results will be discussed for stability analysis of high-temperature maglev in tetail such as: the inflences of the energe loss of HTSC which high speeds running under different applied fields and different cooling medium (including refrigerant and refrigerator) on the stability of High-temperature superconducting maglev, and the relations between the movement of magnetic flux and the energe loss under different temperatures,different operating conditions.Finally, Suspension stability also will be discussed based multi domain HTSC and the array for the point of view of engineering application. A method to improve the stability of high temperature superconducting maglev is proposed, and build a criterion. It provide theoretical guidance for commercial applications of high temperature superconducting maglev.

高温超导磁悬浮稳定性研究具有现实意义，建立超导体内磁通和温度动态变化的数学模型是其数值研究的关键。为了更实际反映这种动态变化，本研究拟通过磁场控制方程、热扩散方程和磁热本构关系，并考虑超导体的各向异性建立数学模型，在研究如何有效模拟高温超导块材内部等效钉扎中心的随机分布和高温超导体非线性问题数值处理方法的基础上用有限元法求解该数学模型；利用该数学模型数值研究不同外磁场励磁和不同冷媒（制冷剂和制冷机）情况下高速运动的高温超导块材能量损耗对高温超导磁悬浮稳定性的影响，及不同温度场、不同冷却条件等情况下，磁通运动与能量损耗的关系，以进行高温超导块体磁悬浮系统稳定性分析，最后从工程应用的角度研究高温超导块材的多畴和多块组合情况下的悬浮稳定性。通过高温超导磁悬浮稳定性分析，提出改进高温超导块材磁悬浮系统稳定性的方案和对策，建立高温超导磁悬浮稳定性判据，为高温超导磁悬浮商业应用提供理论指导依据。

对永磁轨道上方YBCO块材，建立了基于高温超导E-J幂指数模型的磁扩散方程和基于热传导的热扩散方程。采用Fortran语言，借助于Fepg平台编写出了用于求解磁悬浮YBCO块材在对称外磁场下磁悬浮力-热损耗的有限元求解代码。采用这一高温超导磁悬浮求解系统，研究了YBCO块材内部磁、热损耗在超导块材不同悬浮高度下的分布特性；指出了随着临界电流密度的提高，YBCO块材内部电场强度越来越微弱，从而导致热损分布也趋于减弱。