兰州大学机构库 >土木工程与力学学院
盘式YBa2Cu3O7-δ超导线圈失超传播的数值仿真研究
Alternative TitleNumerical Simulation of the Quenching of Superconducting Pancake YBa2Cu3O7-δ Coil
张岳
Thesis Advisor周俊
2017-05-27
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
KeywordYBa2Cu3O7-δ超导线圈 失超传播 2D-3D混合模型 有限元 数值计算
Abstract

高温超导磁体线圈在实际应用过程中可因各种因素的热扰动产生局部热点。在局部热点区域,温度可升至超过超导材料的临界温度,从而使得在线圈局部失超转变为正常态,因此使得超导电流分流至正常态的金属层而产生焦耳热;在局部热点的焦耳热的作用下,局部温度可能过高而引起超导材料的超导电性的急剧下降、甚至完全损坏,因此,研究高温超导线圈的失超区传播行为对于超导磁体的应用和设计具有重要意义。鉴于此,本文针对超导磁体常用的盘式YBa2Cu3O7-δ线圈的失超区传播行为进行了数值仿真研究。

本论文基于Wankan Chan等提出的2D-3D混合维度方法,建立了盘式YBa2Cu3O7-δ超导线圈的COMSOL有限元模型;基于该有限元数值模型,对盘式YBa2Cu3O7-δ超导线圈在77K环境温度下的失超行为进行了细致的数值仿真,研究了各关键参数对失超行为的影响规律。具体主要内容包括:本文着重从失超能量(Qhc、MPZ、MQE)和失超传播速度(NZPV)两个方面对YBCO超导线圈进行研究。1)考虑到在大多数关于YBa2Cu3O7-δ超导线圈的失超行为的实验研究中,通常采用电热丝模拟实际运行中可能出现的初始热源扰动,本论文研究了不同的初始热源(即,不同的热源功率、长度以及工作脉冲)下的失超区传播行为;给出了可使得失超区向外传播的初始热源能量Qh的临界值,及其随热源长度、功率的变化规律;2) 研究了该盘式YBa2Cu3O7-δ超导线圈最小失超传播区MPZ(Minimum Propagation Zone)、最小失超能MQE(Minimum Quench Energy)以及失超传播速度NZPV(Normal Zone Propagation Velocity)随线圈的工作电流的变化规律,同时,分析了MPZ、MQE与初始热源特征的关系,并发现MPZ、MQE对初始热源的特征依赖较弱;3)考虑到YBa2Cu3O7-δ涂层超导带材的稳定层(即,Stabilizer,通常为铜层)的厚度决定了局部热点的焦耳热功率,本论文研究了不同的Stabilizer厚度情况下的失超行为,给出了不同厚度下,分析了YBa2Cu3O7-δ超导线圈的MPZ、MQE、NZPV等关键量的影响。

Other Abstract

In practical application, HTS(High Temperature Superconductor) coil may produce a local hotspot for some thermal disturbance. In the hotspot zone, the temperature of superconductor rises over critical temperature, and the local superconductor transfers to normal. Then the current follows to resistive metal layer to produce Joule heat. Under the influence of local hotspot, the temperature may rise too high to degenerate the property of superconductor and even burn out. Therefore, studying the quenching behavior of superconductor has a profound significance on design and application. For that reason, we made a simulated study for common superconducting magnet of YBa2Cu3O7-δ pancake coil.

The article built a COMSOL FEM model of YBa2Cu3O7-δ pancake coil, which used 2D-3D mixed dimensional method proposed by Wancan Chan. Basing on this FEM model, we had processed a meticulous study on quenching behavior of YBa2Cu3O7-δ pancake coil under the 77K of outer temperature and studied the law of the key parameter and quenching behavior. The article stressed the quenching energy(Qhc, MPZ, MQE) and quenching propagation velocity(NZPV).1) In most experimental study about the behavior of YBa2Cu3O7-δ pancake coil, generally, the researcher uses a heating wire to simulate a thermal disturbance in practice. We studied the behavior of quenching propagation in different heater parameters that includes different heater power, heater length and working pulse. Then, we concluded the critical value of Qh that makes the quenching propagate, and the regulation between Qh and heater length, heater power.2) The article studied the law of operational current with MPZ(Minimum Propagation Zone) and MQE(Minimum Quench Energy) and NZPV(Normal Zone Propagation Velocity) of YBa2Cu3O7-δ pancake coil. Then we analyzed the relation between heater’s characteristic and MPZ, MQE, and found that the relation is feebleness.3) Considering the stabilizer’s thickness of YBa2Cu3O7-δ coated conductor decides the Joule power of local hotpot, the article studied the quenching behavior under different thickness of stabilizer, and analyzed the relation between YBa2Cu3O7-δ pancake coil with MPZ, MQE, NZPV under different thickness of stabilizer.

URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/226056
Collection土木工程与力学学院
Recommended Citation
GB/T 7714
张岳. 盘式YBa2Cu3O7-δ超导线圈失超传播的数值仿真研究[D]. 兰州. 兰州大学,2017.
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