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REBa2Cu3O7-δ(REBCO)高温超导带材具有良好的电磁性能和机械强度,现已成为开发极高场超导磁体的重要基础材料.本文基于T-A 方程提出了一种极高场REBCO 内插磁体的参数化设计方法,该方法在计算中考虑了超导屏蔽电流对磁体中心场强和应变分布的影响,采用分步优化的方式从内向外依次确定各超导线圈的结构参数,每个线圈的优化过程相对独立.基于该设计方法,本文给出了46T全超导磁体中26TREBCO 内插磁体的电磁设计方案,确定了主要线圈参数和工作电流.该内插磁体由4个线圈同轴嵌套串联组成,每个线圈都由REBCO带材绕制而成的双饼线圈(Double Pancake, DP)堆叠而成.基于当前模型计算结果,在给定的20T背景场中,当内插磁体工作电流达到290A时,磁体中心场强可达46T;高温超导线圈中最大环向应变为0.61%,仍然处于危险区域. 相似文献
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用一维网络仿真和解析计算方法对HL-2M 磁体TF 线圈、PF 线圈和CS 线圈水冷却系统进行设计和计算,给出了冷却系统工程设计所需要的水力参数。通过优化冷却系统的资用压力和流量分配,得到满足子系统动力输出的最大流量为400m3•h−1,最大压力为1.8MPa,满足线圈在最大流速4.5m•s−1 下热交换的要求。 相似文献
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本文发展了开放式自屏蔽全身成像高场超导磁共振成像(MRI)磁体的优化设计方法,使设计出来的磁体仅有4 对超导线圈. 这种开放结构的超导MRI磁体优化设计方法集成了线性规划算法和遗传算法. 通过迭代线性规划算法可以在考虑成像区域(DSV)磁感应强度约束、磁场不均匀度约束、5 Gs线范围约束、线圈区域最大磁场值约束和最大环向应力约束的条件下,获得用线量最少的线圈初始形状和位置,同时可以得到每个线圈的层数和每层匝数;通过遗传算法可以提高DSV区域的磁场不均匀度,以达到高质量成像的要求. 这种集成的优化设计方法既可以灵活有效的设计开放式MRI磁体,也可以设计传统的圆柱形MRI磁体,本文通过一个1.2 T的开放式MRI磁体的设计清楚的展示了这种优化方法.
关键词:
线性规划算法
遗传算法
自屏蔽
开放式超导MRI磁体 相似文献
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20 T以上强磁场在高场科学工程中有着不可替代的作用. 电工研究所正在研制一个25 T全超导磁体系统, 包括15 T背景磁场和10 T高温超导内插磁体. 在磁体的设计和优化中, 线圈的数量和种类对于最终优化结果十分关键. 为了研究磁体数量和磁体相关参数的关系, 计算了20 组不同的线圈组合下磁体的优化结果. 优化中除了考虑必要的限制条件以外, 还采用了一种结合局部优化算法和全局优化算法的方法. 通过对比分析发现, 线圈数量和磁体造价之间, 存在一个“V”形的关系. 更进一步地, 本文分析了不同超导体在磁体中应该贡献的最佳磁场, 以及背景磁体统一供电给优化结果带来的影响. 相似文献
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磁共振成像(MRI)的磁体设计首先是确保中心成像区的场值和均匀性, 二是尽可能减少场值耗散的距离即漏磁5Gs 线. 基于此本文提出了一种线性与非线性规划联合优化的方法. 首先将导体作为基本单元, 在预布置线圈的空间范围内构建二维连续导体网格. 通过线性规划搜索满足磁场约束条件的网格电流分布图. 再将存在电流的网格离散为一个个矩形线圈区域, 在保证场值均匀性、 杂散场5 Gs 线范围以及线圈位置间隔、 导体超导线安全裕度的前提下利用非线性规划, 具体确定各个线圈的轴向和径向位置、 线圈内导体层数和各层匝数以及通电流大小等. 采用这种联合优化方法, 不仅节省优化时间, 还可以自行设计线圈形状有利于工程实现. 文中由此方法给出了14 T MRI 磁体的一种设计方案, 依靠4 组线圈使得45 cm 中心球形成像内不均匀度降低到5 ppm, 而高场耗散的5 Gs 线通过磁体自屏蔽减小到15 m 以内. 满足了设计的要求. 相似文献
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Induced current of high temperature superconducting loops by combination of exciting coil and thermal switch 下载免费PDF全文
Jia-Wen Wang 《中国物理 B》2022,31(3):37402-037402
With its commercialization, the second-generation (2G) high temperature superconducting (HTS) RE—Ba—Cu—O (REBCO, RE is rare earth) tape is extensively applied to the superconducting magnets in the high magnetic fields. However, unlike low temperature superconducting (LTS) magnets, the HTS magnet cannot operate in the persistent current mode (PCM) due to the immature superconducting soldering technique. In this paper, an exciting method for two HTS sub-loops, so-called charging and load loops, is proposed by flux pump consisting of exciting coil and controllable thermal switch. Two HTS sub-loops are made of an REBCO tape with two slits. An exciting coil with iron core is located in one sub-loop and is supplied with a triangular waveform current so that magnetic field is generated in another sub-loop. The influence of magnetic flux on induced current in load loop is presented and verified in experiment at 77 K. The relationship between the induced magnetic flux density and the current on the sub-loops having been calibrated, magnetic flux density, and induced current are obtained. The results show that the HTS sub-loops can be excited by a coil with thermal switch and the induced current increases with magnetic flux of exciting coil increasing, which is promising for persistent current operation mode of HTS magnets. 相似文献
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Jozef Pitel Pavol Kováč 《Physica C: Superconductivity and its Applications》2011,471(23-24):1680-1688
A computational model which enables to evaluate the distribution of the critical currents, electric fields and the voltage in the winding of a solenoidal high temperature superconducting (HTS) magnets subjected to an external magnetic field parallel with the magnet axis, was developed. The model comes out from the well-known power law between the electric field and the transport current of the HTS tape short sample. It allows to predict the voltage–current V(I) characteristics of both the pancake coils and the complete magnet. The model was applied to the magnet system consisting of 22 pancake coils made of multifilamentary Bi(2223)/Ag tape at 20 K, which is subjected to an external uniform magnetic field parallel with the coil axis. A rather unexpected behavior of the magnet at different operating conditions (operating current and external magnetic field strength) is predicted, analyzed and reported together with a theoretical explanation. On one hand, the external uniform magnetic field parallel with the coil axis increases the resulting magnetic field strength, however, on the other hand it simultaneously decreases the angle between the resulting magnetic field and the tape surface. Thus, the effect of higher magnetic loading caused by the presence of an external magnetic field strength which is acting on individual turns located close to the coil’s flanges is compensated by more favorable orientation of the tape with respect to the resulting magnetic field. As a result, increase in the critical currents of these turns is expected. Further, the results indicate, that in case of the high field HTS insert coils the anisotropy in the Ic(B) characteristic does not play a substantial role. As a consequence, the technology of the production of the tapes for high field insert HTS coils should concentrate rather on the tapes having the current carrying capacity as high as possible, than on the attempt how to decrease the anisotropy in the Ic(B) by changing the architecture of the filaments in the tape. 相似文献
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实验和数值模拟超导绕组的机械特性 总被引:4,自引:0,他引:4
为了减少环氧浸渍的超导磁体的锻炼和退化效应,基于实验和数值模拟研究了在热应力的电磁力的条件下超导绕组的机械特性;研究的基本目的是决定超导复合线圈基本的材料特性,其中复合超导绕组的杨氏模量和热收缩系数是基本的参数,使用这些参数我们可以用有限元方法精确地研究超导磁体的机械特性,通过分析各种超导磁体的设计,判断好的和坏的磁体设计,从而发展新的超导磁体的设计标准,形成超导磁体的设计和建造的基本方法,本中我们将通过实验和FEA模拟研究复合绕组的基本参数和应用特性。 相似文献
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Jeglic P Lebar A Apih T Dolinsek J 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2001,150(1):39-42
The resonance frequency-space and the frequency gradient-space relations are evaluated analytically for the static fringe magnetic field of superconducting magnets used in the NMR diffusion measurements. The model takes into account the actual design of the high-homogeneity magnet coil system that consists of the main coil and the cryoshim coils and enables a precise calibration of the on-axis magnetic field gradient and the resonance frequency inside and outside of the superconducting coil. 相似文献
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M. S. Novikov D. P. Ivanov S. I. Novikov S. A. Shuvaev 《Physics of Atomic Nuclei》2015,78(10):1148-1154
Application of current-carrying elements (CCEs) made of second-generation high-temperature superconductor (2G HTS) in magnet systems of a fusion neutron source (FNS) and other fusion devices will allow their magnetic field and thermodynamic stability to be increased substantially in comparison with those of low-temperature superconductor (LTS) magnets. For a toroidal magnet of the FNS, a design of a helical (partially transposed) CCE made of 2G HTS is under development with forced-flow cooling by helium gas, a current of 20–30 kA, an operating temperature of 10–20 K, and a magnetic field on the winding of 12–15 T (prospectively ~20 T). Short-sized samples of the helical flexible heavy-current CCE are being fabricated and investigated; a pilot-line unit for production of long-sized CCE pieces is under construction. The applied fabrication technique allows the CCE to be produced which combines a high operating current, thermal and mechanical stability, manufacturability, and low losses in the alternating modes. The possibility of fabricating the CCE with the outer dimensions and values of the operating parameter required for the FNS (and with a significant margin) using already available serial 2G HTS tapes is substantiated. The maximum field of toroidal magnets with CCEs made of 2G HTS will be limited only by mechanical properties of the magnet’s casing and structure, while the thermal stability will be approximately two orders of magnitude higher than that of toroidal magnets with LTS-based CCEs. The helical CCE made of 2G HTS is very promising for fusion and hybrid electric power plants, and its design and technologies of production, as well as the prototype coils made of it for the FNS and other tokamaks, are worth developing now. 相似文献
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Tieng QM Vegh V Brereton IM 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2009,196(1):7-11
A globally optimal superconducting magnet coil design procedure based on the Minimum Stored Energy (MSE) current density map is outlined. The method has the ability to arrange coils in a manner that generates a strong and homogeneous axial magnetic field over a predefined region, and ensures the stray field external to the assembly and peak magnetic field at the wires are in acceptable ranges. The outlined strategy of allocating coils within a given domain suggests that coils should be placed around the perimeter of the domain with adjacent coils possessing alternating winding directions for optimum performance. The underlying current density maps from which the coils themselves are derived are unique, and optimized to possess minimal stored energy. Therefore, the method produces magnet designs with the lowest possible overall stored energy. Optimal coil layouts are provided for unshielded and shielded short bore symmetric superconducting magnets. 相似文献
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Yu. A. Shishov 《Physics of Particles and Nuclei》2006,37(3):444-473
This is a retrospective review of superconducting magnets for spectrometers of high-energy particles. The magnets are grouped according to the purpose of the spectrometers and the shape of coils. Data on the thermostatting and electrical protection of the coils are presented. Design features of various-type magnets are described. The first large superconducting solenoids were constructed for hydrogen bubble chambers. Further progress was related to the construction of spectrometers that were designed for experiments at colliders and included solenoids with radiation-transparent walls. Along with solenoids, dipole and toroidal magnets were used in spectrometers; some designs of such magnets are also discussed in the review. A special type of polarizing solenoid is used in polarized targets. Spectrometers with magnets of various coil shapes were created for astrophysical research. As an instance, the original radiation-transparent solenoid and the dipole magnet with a cryocooler are represented. Prospects for the future development of magnets are connected with the use of high-temperature superconductors (HTS). Information on the present situation in engineering the HTS ribbon and solenoids is given. 相似文献
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高温超导磁体在闭环运行时,可以提供稳定磁场,但是由于高温超导带材无法实现无阻焊接,成为高温超导磁体闭环运行的技术瓶颈.本文利用第二代高温超导带材制备闭环超导环,采用内部励磁和外部励磁对超导环进行励磁,在液氮温度中(77 K)测量超导环的中心俘获磁场.结果表明超导环在内部励磁俘获的磁场值比外部励磁俘获的磁场值高;外部励磁中,超导环中插入铁芯柱能提高俘获场;内部励磁中,超导环在螺线管闭环运行俘获的磁场值比开环运行俘获的磁场值高.结果对于高温超导闭环磁体励磁和高温超导带材磁通动力学研究具有很重要参考价值. 相似文献