YBCO高温超导线圈复杂多层结构热传导机理及能量耗散优化模型

YBCO superconductors are considered as superconducting materials for high-voltage applications in the temperature range of liquid nitrogen due to their excellent high-field properties. However, there are problems to be solved in the practical applications: The thermal conduction mechanism at the anisotropic materials interface of YBCO high-temperature superconducting tapes under the action of heat and force is unknown; Insulating layers materials of superconducting tapes are bad conductors of heat. It is difficult to dissipate energy after quench and heat production of superconductors which seriously threatens the safe and stable operation of equipment. Firstly, this topic proposes magnetic microscopic method for measuring the positional temperature dynamic distribution, and the surface temperature and surface current density distribution characteristics of superconducting tapes are studied through experiments on a macro scale. The effect of microstructural changes on thermal conductivity at interface of anisotropic materials by non-equilibrium molecular dynamics method, and heat transfer mechanism are revealed. 3D/2D mixed dimension models of superconducting coils are structured, the anisotropic heat conduction behaviors and their key influencing factors under thermal stress after quenching are analyzed, and the principles of thermal conduction under transient states of superconducting coils are explained. Based on the universal kriging method, the global optimization algorithm are studied and the energy dissipation optimization design models of the superconducting coils are established. The research results provide theoretical basis for preparation of superconducting coils, quench protection and structural optimization designs of superconducting power equipment.

YBCO超导体由于其优异的高场性能，被看作是可在液氮温区实现强电应用的超导材料。然而在实际应用中仍存在以下问题：①YBCO高温超导带材在热、力作用下异性材料交界面热传导机理不明；②超导带材的绝缘层通常采用热的不良导体，失超后能量难以耗散，严重威胁设备的安全稳定运行。本课题首先提出一种基于磁显微法的可定位温度动态分布测量方法，从宏观上实验研究超导带材的表面温度及电流密度动态分布变化规律；基于非平衡态分子动力学方法，分析微观结构变化对于异性材料交界面热导的影响规律，揭示其交界面传热机理；据此建立超导线圈3D/2D混合维度有限元模型，分析失超后热应力作用下各向异性热传导行为及其关键影响因素，阐释暂态情况下超导线圈复杂多层结构热传导机制；基于泛克里金法，研究适用于超导线圈的全局优化算法，并建立超导线圈能量耗散优化模型。研究成果可为超导带材制备以及超导电力设备的失超保护和结构优化提供理论依据。

YBCO高温超导体由于其优异的性能，被广泛应用于超导电力设备中。本项目研究了高温超导线圈复杂多层结构的热传导过程，分析了其关键影响因素，提出了高温超导线圈的能量耗散模型，具体得到以下研究结果：1）基于磁显微镜的可定位温度动态分布测量方法，得到超导带材温度分布和电流密度变化特性。2）根据高温超导带材电磁热耦合有限元模型，得到超导带材层间温度特性，进一步分析得到超导带材温度和电流动态转移的过程。3）在微观视角下，对超导带材应力应变退化机理进行分析，并得到了在不同应力作用下的电流密度分布特性。4）搭建高温超导线圈2D/3D电磁热多物理场耦合模型，分析超导线圈电磁分布和热场分布特性，揭示超导线圈匝间热传导机制。分析了在绕制形变以及失超后热应力作用下超导带材层间微观结构变化及其与材料（各向异性）热传导的关联关系，获得其横向热传导与失超传播、轴向热传导与能量耗散的关联关系，阐释暂态情况下超导线圈的热传导机理。5）基于不同绝缘材料在低温下的导热特性、力学特性，绝缘材料与超导带材交界面物理结构以及超导线圈结构，构建了高温超导线圈的能量耗散优化模型，研究了影响其能量耗散的关键影响因素。本项目的研究成果为超导带材制备及其超导电力设备的失超保护和结构优化提供参考。最后，按照项目计划，完成了项目指标，共发表SCI论文4篇，EI论文6篇，参加国内外会议共6次，授权国家发明专利3项，培养硕士研究生3名。