一种混合高温超导磁体及其电磁特性研究

近年来, 高温超导磁体由于载流能力高、 磁场强等优点在磁悬浮列车、 医疗成像、 飞轮储能器等系统具有广阔的应用前景. 在这些应用中, 工作面上磁场越强, 系统的性能越优. 高温超导块材能够俘获强磁场, 但因为尺寸的限制, 其磁场发散区域小, 在大气隙条件下工作面区域磁场弱. 相比而言, 高温超导线圈的尺寸不受限制, 但其磁场会随着口径的增大而降低. 因此, 本文将高温超导线圈和块材结合, 提出了一种结构紧凑、 口径大、 磁场强的混合高温超导磁体. 同时, 利用有限元仿真软件建立混合高温超导磁体的二维轴对称自洽模型并进行了实验验证, 仿真计算了混合高温超导磁体的磁场分布以及不同温度下的临界电流和最大磁场强度. 结果表明, 混合高温超导磁体可显著增加工作面的磁场, 相比于独立的高温超导线圈和高温超导块材最大磁场分别最小提升了102% 和12% .另外, 混合高温超导磁体工作面上的有效磁通相比于高温超导块材也提高了.     

Transient multi-physics behavior of an insert high temperature superconducting no-insulation coil in hybrid superconducting magnets with inductive coupling

A transient multi-physics model incorporated with an electromagneto-thermomechanical coupling is developed to capture the multi-field behavior of a single-pancake (SP) insert no-insulation (NI) coil in a hybrid magnet during the charging and discharging processes. The coupled problem is resolved by means of the finite element method (FEM) for the magneto-thermo-elastic behaviors and the Runge-Kutta method for the transient responses of the electrical circuits of the hybrid superconducting magnet system. The results reveal that the transient multi-physics responses of the insert NI coil primarily depend on the charging/discharging procedure of the hybrid magnet. Moreover, a reverse azimuthal current and a compressive hoop stress are induced in the insert NI coil during the charging process, while a forward azimuthal current and a tensile hoop stress are observed during the discharging process. The induced voltages in the insert NI coil can drive the currents flowing across the radial turns where the contact resistance exists. Therefore, it brings forth significant Joule heat, causing a temperature rise and a uniform distribution of this heat in the coil turns. Accordingly, a thermally/mechanically unstable or quenching event may be encountered when a high operating current is flowing in the insert NI coil. It is numerically predicted that a quick charging will induce a compressive hoop stress which may bring a risk of buckling instability in the coil, while a discharging will not. The simulations provide an insight of hybrid superconducting magnets under transient start-up or shutdown phases which are inevitably encountered in practical applications.     

基于共耦合谐振单元结构的高温超导五工器

文章采用共耦合谐振单元结构设计制作了一款高温超导五工器, 五工器五个信道的工作频率分别为807.5 MHz、810.5 MHz、813.5 MHz、816 .5 MHz、819 .5 MHz, 每信道通带宽度均为1 MHz. 滤波器电路用镝钡铜氧(DyBCO) 双面超导薄膜制作, 衬底为3 英寸0.5 mm 厚度的氧化镁( MgO) 基片. 文章给出了高温超导五工器的等效电路、 理论曲线、 耦合参数、Sonnet 软件全波电磁场模拟仿真和实际测试曲线, 取得较为理想的结果