Xue Cun, Ren Han-Xi, Jia Peng, Wang Qing-Yu, Liu Wei, Ou Xian-Jin, Sun Liang-Ting, Silhanek Alejandro V
School of Mechanics, Civil Engineering and Architecture, Northwestern Polytechnical University, 710072, Xi'an, China.
School of Aeronautics, Northwestern Polytechnical University, 710072, Xi'an, China.
Nat Commun. 2024 Dec 1;15(1):10454. doi: 10.1038/s41467-024-54406-8.
Superconductors play a crucial role in the advancement of high-field electromagnets. Unfortunately, their performance can be compromised by thermomagnetic instabilities, wherein the interplay of rapid magnetic and slow heat diffusion can result in catastrophic flux jumps, eventually leading to irreversible damage. This issue has long plagued high-J NbSn wires at the core of high-field magnets. In this study, we introduce a large-scale GPU-optimized algorithm aimed at tackling the complex intertwined effects of electromagnetism, heating, and strain acting concomitantly during the quenching process of superconducting coils. We validate our model by conducting comparisons with magnetization measurements obtained from short multifilamentary NbSn wires and further experimental tests conducted on solenoid coils while subject to ramping transport currents. Furthermore, leveraging our developed numerical algorithm, we unveil the dynamic propagation mechanisms underlying thermomagnetic instabilities (including flux jumps and quenches) within the coils. Remarkably, our findings reveal that the velocity field of flux jumps and quenches within the coil is correlated with the cumulated Joule heating over a time interval rather than solely being dependent on instantaneous Joule heating power or maximum temperature. These insights have the potential to optimize the design of next-generation superconducting magnets, thereby directly influencing a wide array of technologically relevant and multidisciplinary applications.
超导体在高场电磁铁的发展中起着至关重要的作用。不幸的是，它们的性能可能会受到热磁不稳定性的影响，在这种情况下，快速的磁扩散和缓慢的热扩散相互作用会导致灾难性的磁通跳跃，最终导致不可逆转的损坏。这个问题长期以来一直困扰着作为高场磁体核心的高J值NbSn导线。在本研究中，我们引入了一种大规模的GPU优化算法，旨在解决超导线圈淬火过程中同时作用的电磁、加热和应变的复杂交织效应。我们通过与从短多丝NbSn导线获得的磁化测量结果进行比较，并在螺线管线圈上施加斜坡传输电流时进行进一步的实验测试，来验证我们的模型。此外，利用我们开发的数值算法，我们揭示了线圈内热磁不稳定性（包括磁通跳跃和失超）的动态传播机制。值得注意的是，我们的研究结果表明，线圈内磁通跳跃和失超的速度场与一个时间间隔内的累积焦耳热相关，而不仅仅取决于瞬时焦耳热功率或最高温度。这些见解有可能优化下一代超导磁体的设计，从而直接影响广泛的技术相关和多学科应用。
