超导悬浮系统悬浮力的分析.docx

中国科学院电工研究所硕士学位论文超导悬浮系统的悬浮力分析姓名:王琳申请学位级别:硕士专业:电工理论与新技术指导教师:王秋良 20060601 摘要摘要超导悬浮系统是超导体重要的应用领域之一。它利用超导体的抗磁性和钉扎性使物体悬浮起来。与其它传统的物理悬浮相比有很多无法比拟的优点。本文从描述超导体宏观电磁特性的 Maxwell 方程出发,基于超导体电磁本构的非线性 E-J 关系和超导体结构的特点,利用有限元方法和计算机快速计算的优点,建立定量分析超导悬浮系统的数值计算方法。针对由圆柱形超导体-超导线圈组成的低温超导悬浮系统,结合基于磁矢量位A方法的超导体偏微分方程,推导出计算超导体屏蔽电流的有限元方程组,求得低温悬浮系统的静态悬浮力特性,分析了线圈电流幅值和线圈尺寸对静态悬浮力的影响规律。并用此法对由超导球体-超导线圈组成的悬浮系统进行分析。针对由圆柱形超导体-永磁体组成的高温超导悬浮系统,结合基于电流矢量位T方法的超导体偏微分方程,得到高温超导体内部复杂的屏蔽电流分布变化, 本文选取两组已经有实验结果的系统参数进行数值定量模拟计算,得到的两组静态悬浮力-间隙曲线都与实验结果相吻合,悬浮力曲线有很强的磁滞特性,屏蔽电流的分布从本质上解释了这个现象。最后详细分析了系统的材料参数、尺寸参数和场冷高度对静态悬浮力的影响规律,得到了很多对实际应用有帮助的结果。最后用磁通蠕变与流动模型对悬浮系统的动态悬浮力进行了初步分析,得到了动态悬浮力对时间的依赖关系,通过与实验结果相比较,发现用磁通蠕变与流动模型比临界态模型能更准确地反映悬浮系统的动态特性。总之,本文定量分析了超导悬浮系统的静态特性,为将来的进一步理论分析奠定了坚实的基础,同时这些结果对实际的工程设计有很好的指导作用。关键词: 超导悬浮系统,电磁本构关系,有限元方法,屏蔽电流分布, 静态悬浮力,动态悬浮力 I ABSTRACT ABSTRACT Superconducting suspension system isone of the important applications of superconductors, which can suspend up the objects by the ic and pinning nature of superconductor. Compared with other traditional physical suspended it has many distinct merits. This article describes macroscopic ic characteristics of superconductor with the Maxwell equations, based on the nonlinear ic constitutive E-J relations and structural characteristics of superconductor, making use of finite element methods puter, which can plicated problem in a short time, the numerical methods which quantitatively analyze superconducting suspension system are established. In the low-temperature superconducting suspension system posed of columned superconductor and superconductive coil, based on superconductor partial differential equation that deduced by the ic vector potential A method, extrapolated finite element equations to calculate superconductor shielding current, and deal with the static levitation characteristics of cryogenic suspension system. Obtained the relationship between static levitation force and the current in the levitation coil, geometric size of the levitation coil. Furthermore analyzed t