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31.
超导磁体系统产生的磁场作用下的微重力环境 总被引:2,自引:0,他引:2
超导磁体系统产生的磁场力可抑制晶体生长过程中的自然对流,从而提高晶体结晶质量。通过理论分析,得到了实现微重力环境所要求的磁场强度分布。针对特定结构的超导磁体系统,数值模拟得到了不同晶体结晶过程中自然对流完全抑止所需要的线圈电流密度,以及工作空间内的磁场强度和磁加速度。以圆筒内水的自然对流为例,分别得到了重力作用下的流场和温度场,以及超导磁体系统微重力区内的流场和温度场。结果表明:通过特定的超导磁体结构和不同电流密度,可实现不同晶体结晶过程的微重力环境,达到抑止自然对流的目的。 相似文献
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The stress-strain state of the structure is a matter of interest to designer. The strain measurement of superconducting magnets at cryogenic temperature is a specific technique. Based on strain measurement of TF coil case for EAST, this paper presents a measuring technique at cryogenic temperature and on intense magnetic field. The compensation methods for both temperature and magnetic field effects of the gauges, together with the measured results are involved, and the discussions of the measured results are given in the paper. 相似文献
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Minseok Joo 《低温学》2005,45(5):343-347
This paper dealt with current-limiting performances of an inductive high-Tc superconducting fault current limiter with an auxiliary coil. The fault current limiter mainly consists of the primary copper coil, secondary high-Tc superconducting rings, and auxiliary high-Tc superconducting coils, which are magnetically coupled through three-legged core. The superconducting fault current limiter as a series element in the power system is inserted to limit the fault current. The device presents fast variable-impedance features in the event of a fault condition. The fault current peak can become relatively large for certain ranges of the flux and the fault instant due to the core saturation. The auxiliary coil proposed in this paper was proven to increase the impedance of the SFCL up to more than 31% while preventing the core saturation. 相似文献
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毛剑珊 P.Phillips 罗家融 徐宇鸿 赵君煜 张先梅 万宝年 张守银 揭银先 吴振伟 胡立群 刘胜霞 石跃江 李建刚 HT-M&HT- group 《等离子体科学和技术》2003,5(1):1641-1650
The Experiments of Modulated Toroidal Current were done on the HT-6M tokamak and HT-7 superconducting tokamak. The toroidal current was modulated by programming the Ohmic heating field. Modulation of the plasma current has been used successfully to suppress MHD activity in discharges near the density limit where large MHD m = 2 tearing modes were suppressed by sufficiently large plasma current oscillations. The improved Ohmic confinement phase was observed during modulating toroidal current (MTC) on the Hefei Tokamak-6M (HT-6M) and Hefei superconducting Tokamak-7 (HT-7). A toroidal frequency-modulated current, induced by a modulated loop voltage, was added on the plasma equilibrium current. The ratio of A.C. amplitude of plasma current to the main plasma current △Ip/Ip is about 12% ~ 30%. The different formats of the frequency-modulated toroidal current were compared. 相似文献
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We have reported that the alternating current (ac) losses in a 66 kVrms 3-core high-TC superconducting (HTS) transmission cable fabricated by Tokyo Electric Power Company and Sumitomo Electric Industries Ltd. are calculated correctly by using an electric-circuit model. According to the calculated results, the circumferential field losses are dominant in the total ac losses in compared with the self-field losses and the axial-field losses. The helical pitches of each layer in the HTS cable are designed to obtain almost same layer currents, which gives the minimum self-field losses. We think that the optimum helical pitches giving the minimum total losses are different from the helical pitches designed by the companies and calculate the optimum values in the condition of the same helical direction of each layer in the cable. As a result, for example, it is found that the ac loss of 2.1 W m−1 cc−1 at transporting 1 kArms can be reduced to 1.8 W m−1 cc−1 (about 14% reductions) after redesigning the cable with the optimum helical pitches. The optimum helical pitches are obtained for each given transport current. After redesigning, the distribution of layer currents is not uniform and the circumferential fields are reduced. 相似文献
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