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临界电流值是描述Bi2223高温超导带材性能的一个基本参数,在一定的温度条件下,Bi2223高温超导带材的临界电流是带材所在位置磁场大小和磁场方向的函数,其短样的临界电流值可以通过四引线法测量,单根超导带材的自场很小,磁场对临界电流的影响可以忽略.高温超导磁体的临界电流被定义成引发该磁体失超的最小电流,高温超导磁体的自场比单根超导带材的自场要大得多,磁体各个位置的磁场大小和方向各不相同,很难用理论的方法准确计算磁体的临界电流.对于高温超导磁体而言,除了磁场的影响因素以外,绕制磁体所用的超导带材自身的均匀性也是影响其临界电流的一个重要因素.本文对这两个因素进行探讨,并着重讨论高温超导带材自身的均匀性对临界电流大小的影响,本文的结论可以为高温超导磁体的设计、磁体绕制时带材的选择、磁体运行时安全工作电流的确定提供帮助. 相似文献
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用国产Bi2223/Ag带(西北有色金属研究院提供)设计的中心场3.0T.贮能35kJ的传导冷却高温超导磁体正在建造中.磁体由绕组内径150mm.外径272mm的32个双饼磁体组成.磁体在温度T=20K下.设计临界电流Ic=132A.额定运行电流I=100A.在T=20K附近进行四双饼组合磁体实验,得到磁体Ic=140A,中心场Bcc=1.14T,相应Bi2223/Ag带上最大轴向场Brmax=1.91T.Bi2223/Ag带上最大垂直场Brmax=1.14T.四双饼组合磁体的实验结果预示:35kJ HTS贮能磁体的设计目标能够达到. 相似文献
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采用输运电流方法测试了37芯Bi2223带材的平均错配角.带材的错配角随带材厚度的降低而减小,同时带材Jc升高.但过薄的带材由于加工不稳定易导致Ag/超界面不规则现象,并破坏界面晶粒取向,造成错配角增大. 相似文献
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Bi2223/Ag高温超导带材连接技术的研究 总被引:4,自引:0,他引:4
钎焊连接是Bi2223/Ag高温超导带材实际应用最多的连接工艺,包括焊接温度、焊料和中间层设计等工艺环节.本文首先对PIT工艺制备的Bi2223/Ag高温超导带材开展了热处理温度-Ic影响试验,通过实验筛选出适合Bi系带材的焊接加热温度.用Sn96CuAg 、Sn60PbAg、Sn60PbSb等三种焊料进行了Bi2223/Ag高温超导带材钎焊实验,研究了钎焊工艺对焊接接头低温电阻影响,建立焊接接头电阻数学表达公式,并利用数学模型讨论了焊接中间层设计优化问题. 相似文献
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Bi2 2 2 3银包套超导带材是研制高温超导磁体和高温超导强电应用的基础。文中就对高温超导磁体最大运行电流有重要影响的 Bi2 2 2 3银包套带材侧向弯曲形变进行了初步探讨 ,就不同的侧向弯曲率对超导带载流能力的影响进行了实验测试 ,并提出了提高 HTS磁体最大运行电流的方法。 相似文献
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ITER电流引线高温超导叠制作工艺及性能测试 总被引:2,自引:0,他引:2
ITER高温超导电流引线载流能力最大要达到68 kA,一根电流引线共需要1000多根银金基Bi-2223高温超导带并联.这些高温超导带分成90叠,每叠由12层带组成.银金基Bi-2223带价格是普通银基Bi系带的4~5倍,而目前欧洲超导公司提供的超导叠的报价几乎是其带价格加倍,所以开发超导叠的制作工艺是非常有价值的.本文详细的介绍了超导叠的真空钎焊制作工艺,并进行了77 K下超导带的接头电阻测试和77 K自场下的临界电流测试,以及模拟在实际运行温度65~5 K条件下高温超导叠的载流能力测试和接头电阻的测试.测试结果证明了此工艺的可行性. 相似文献
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本文阐述了用于高温超导磁体电磁结构优化设计的一种新方法,与一般优化方法不同之处在于其不用定义磁体的初始结构形状,采用该方法可以得到满足规格和性能要求的较佳磁体结构.通过此方法优化设计了一个中心磁场为3T的Bi系高温超导磁体,其设计结果与满足同样要求且经过优化的单螺管高温超导磁体的设计结果作了对比,由结果表明该方法具有很好的优化效果. 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