NbTi CICC导体横向机械性能分析
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摘要
超导导体的力学性能是决定导体载流性能的重要影响因素之一,构成超导磁体的超导电缆在运行过程中受电磁力、热应力的作用,会导致其内部超导线产生应变,进而影响其载流性能和交流损耗,因此研究电磁循环载荷对超导电缆的影响有着重要的意义。对国际热核聚变实验堆中极向场线圈中Nb Ti超导导体进行机械压缩实验,并从形变量、弹性模量、弹性功等方面,对其机械强度进行分析。该方法可以在不进行电磁循环测试的情况下快速判断导体机械性能,为导体设计提供初步性能评判依据。结果显示,PF1-6NbTi超导导体相对于测试的其他PF导体在相同工况下,累积形变量与最大形变量更小。通过进一步对导体结构设计进行对比分析,发现低空隙率以及短节距绞线可以有效提高电缆机械性能。
The mechanical properties of superconducting conductors are one of the important factors affecting the current transport performance of conductor. The superconducting cables in superconducting magnets are subjected to the Lorentz force and thermal stress during operation,which will cause strain on the superconducting wires and performance degradation.Therefore,it is significance to study the transverse mechanical properties of superconducting conductors. The mechanical compression of Nb Ti superconducting conductor in the polar field coils of ITER was carried out and studied by the deformation,elastic modulus and elastic strain energy. The results show that the PF1-6 Nb Ti superconducting conductor has a smaller cumulative shape and maximum shape variable under the same conditions than the other PF conductors tested. By further analyzing the conductor structure design,it is found that the low void fraction and the short twist pitch can effectively improve the mechanical properties of the cable.
The mechanical properties of superconducting conductors are one of the important factors affecting the current transport performance of conductor. The superconducting cables in superconducting magnets are subjected to the Lorentz force and thermal stress during operation,which will cause strain on the superconducting wires and performance degradation.Therefore,it is significance to study the transverse mechanical properties of superconducting conductors. The mechanical compression of Nb Ti superconducting conductor in the polar field coils of ITER was carried out and studied by the deformation,elastic modulus and elastic strain energy. The results show that the PF1-6 Nb Ti superconducting conductor has a smaller cumulative shape and maximum shape variable under the same conditions than the other PF conductors tested. By further analyzing the conductor structure design,it is found that the low void fraction and the short twist pitch can effectively improve the mechanical properties of the cable.
引文
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[9] SANABRIA C,et al. Metallographic autopsies of fullscale ITER prototype cable-in-conduit conductors after full cyclic testing in SULTAN:III. The importance of strand surface roughness in long twist pitch conductors[J]. Superconductor Science and Technology,2016. 29(7):074002.
[10] SANABRIA C,et al. Evidence that filament fracture occurs in an ITER toroidal field conductor after cyclic Lorentz force loading in SULTAN[J]. Superconductor Science and Technology,2012,25(7):075007.
[2] BRESCHI M,et al. Results of the TF conductor performance qualification samples for the ITER project[J].Superconductor Science&Technology, 2012, 25(9):095004.
[3]QIN J,et al. New design of cable-in-conduit conductor for application in future fusion reactors[J]. Superconductor Science and Technology, 2017, 30(11):115012.
[4]戴超,等. Nb Ti、Nb3Sn超导线拉伸性能研究[J].低温物理学报,2014,36(6):475-481.
[5]QIN J G,et al. Manufacture and test of Bi-2212 cablein-conduit conductor[J]. IEEE Transactions on Applied Superconductivity,2017,27(4):1-5.
[6]MUZZI L,et al. Design,manufacture,and test of an 80k A-class Nb3Sn cable-in-conduit conductor with rectangular geometry and distributed pressure relief channels[J]. IEEE Transactions on Applied Superconductivity,2017,27(4):1-6.
[7] SANABRIA C,et al. Metallographic autopsies of fullscale ITER prototype cable-in-conduit conductors after full testing in SULTAN:I. The mechanical role of copper strands in a CICC[J]. Superconductor Science and Technology,2015,28(8):085005.
[8] SANABRIA C,et al. Metallographic autopsies of fullscale ITER prototype cable-in-conduit conductors after full cyclic testing in SULTAN:II. Significant reduction of strand movement and strand damage in short twist pitch CICCs[J]. Superconductor Science and Technology,2015. 28(12):125003.
[9] SANABRIA C,et al. Metallographic autopsies of fullscale ITER prototype cable-in-conduit conductors after full cyclic testing in SULTAN:III. The importance of strand surface roughness in long twist pitch conductors[J]. Superconductor Science and Technology,2016. 29(7):074002.
[10] SANABRIA C,et al. Evidence that filament fracture occurs in an ITER toroidal field conductor after cyclic Lorentz force loading in SULTAN[J]. Superconductor Science and Technology,2012,25(7):075007.