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Electromagnetic levitation has developed from a pure physical phenomenon into a practical containerless processing technique in the fields of both applied physics and materials science. In order to obtain a better understanding of this processing technique, two typical levitation coils were designed and the physical characteristics in levitation droplets suspended in these two coils, such as electromangetic field, levitation force field, total levitation force, and power absorption, were analyzed numerically and calculated in this paper. It was found that the eddy current density, together with the magnetic flux density and levitation force density, increases rapidly with radius as it approaches sample surface. The maximum levitation force produced by coil A is larger than that of coil B, whereas the levitated sample can obtain less power absorption at the equilibrium position in the former coil than that in the latter one. Moreover, the calculated results also demonstrated that the levitation ability decreases as the atomic number increases. The larger the material's electrical resistivity, the easier the samples can obtain more power absorption. 相似文献
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We produced RE-123 infiltrated by Sm123 superconductors by the melt growth method. The samples have been investigated in terms of X-ray diffraction (XRD) analysis, AC susceptibility, levitation force, and a magnetic stiffness calculation. The X-ray diffraction analysis showed that the Sm123 and Y123 phases were insufficiently grown at the selected sintering temperature of 1040 °C. The transition temperature of the IP Sample is 94.28 K from the AC Susceptibility (at 1 KHz and 4 Oe applied AC field) measurement. The magnetic stiffness was calculated using our newly designed vertical magnetic levitation force measurement system. It has a Nb-Fe-B permanent magnet (∼0.5T) at 77 K with the Zero Field Cooled process. The magnetic stiffness was calculated using the data of the levitation force. The descending experimental results showed that the most significant F0was contained in the sample I5 (F0 = 9.034 N) and the largest constant b value was determined in the sample IP (b = 0.3320 mm−1). But in the ascending results, the most significant F0 is 8.604 N, and the largest constant b is 0.3047 mm−1, both calculated in the IP sample. Considering the oxygen content effects on the magnetic stiffness, one can infer that it has been positively affected by an increase in the Sm123 infiltration. These results indicatethat the produced samples could be applied to bearing systems, magnetic sensors and other technological applications. 相似文献
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A novel layer deletion method is used to experimentally investigate the effect of induced shielding current transmission (ISCT)
in the longitudinal direction on the levitation force of a single-domain YBa2Cu3O7−x (YBCO) cylindrical superconductor (ϕ30×7 mm). In the experiment the sample was gradually sliced into two equal sheets, at
the middle height along a diameter with 5 mm every step. The experimental results show that the levitation force is closely
related with the ISCT in the longitudinal direction. Any layer deletion, even a small piece of layer deletion can reduce the
levitation force of the sample. After the whole layer was deleted the levitation force can diminish about 50%. It is also
found that the levitation force is directly proportional to the effective factor of surface area, which is equal to the top
surface area divided by the total surface area parallel to the top surface of the sample. 相似文献
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W. Liu J.S. Wang X.L. Liao S.J. Zheng G.T. Ma J. Zheng S.Y. Wang 《Physica C: Superconductivity and its Applications》2011,471(5-6):156-162
To a high-Tc superconducting (HTS) maglev system which needs large levitation force density, the magnetized bulk high-Tc superconductor (HTSC) magnet is a good candidate because it can supply additional repulsive or attractive force above a permanent magnet guideway (PMG). Because the induced supercurrent within a magnetized bulk HTSC is the key parameter for the levitation performance, and it is sensitive to the magnetizing process and field, so the magnetized bulk HTSC magnets with different magnetizing processes had various levitation performances, not only the force magnitude, but also its force relaxation characteristics. Furthermore, the distribution and configuration of the induced supercurrent are also important factor to decide the levitation performance, especially the force relaxation characteristics. This article experimentally investigates the influences of different magnetizing processes and trapped fields on the levitation performance of a magnetized bulk HTSC magnet with smaller size than the magnetic inter-pole distance of PMG, and the obtained results are qualitatively analyzed by the Critical State Model. The test results and analyses of this article are useful for the suitable choice and optimal design of magnetized bulk HTSC magnets. 相似文献
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I. V. Aleksandrova E. L. Koshelev A. I. Nikitenko T. P. Timasheva E. R. Koresheva 《Journal of Russian Laser Research》2018,39(2):140-155
Creation of a delivery system based on noncontact positioning and transport of the cryogenic fuel targets represents one of the major tasks in a general program of inertial fusion energy (IFE) research. The purpose is to maintain the fuel layer quality during acceleration and injection of IFE targets at the focus of a powerful laser facility or IFE reactor. The program of the Lebedev Physical Institute (LPI) includes much development work on creation of different designs of the hybrid accelerators for IFE target transport with levitation. One of the main directions is an electromagnetic accelerator (EM-AC) + PMG system, where PMG is the permanent magnet guideway. The operational principle is based on quantum levitation of type-II high-temperature superconductors (HTSC) in the magnetic field. At the current stage, conceptual development of “EM-AC + PMG” hybrid accelerator is complete, and proof-of-principle experiments in mutually normal magnetic fields are made. This accelerator is a combination of the acceleration system (field coils generating the traveling magnetic waves) and the levitation system (PMG including a magnetic rail or magnetic track). The results obtained show that the HTSCs can be successfully used to maintain friction-free motion of HTSC sabots over the PMG, and also provide the required stability of the levitation height over the whole acceleration length due to the pinning effect. Additionally, using the driving body from MgB2 superconducting coils as a sabot component (critical current 5,000 A at magnetic induction 0.25 T) allows one to reach injection velocities of 200 m/s under 400 g at 5 m acceleration length. 相似文献
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高温超导体因其无源自稳定的特性,受到许多学者的重视,具有广阔的应用前景.目前针对高温超导块材悬浮性能的研究主要集中于由永磁体产生的低磁场环境.本文基于超导磁体平台提供的强磁场环境,通过改变高温超导块材不同的场冷高度,实验研究了高温超导块材悬浮力与垂向磁场变化量的关系.研究结果表明随着垂向磁场变化量的增加,高温超导块材的悬浮力增长趋缓,并最终出现悬浮力饱和的现象.本文还对比了YBCO 和Gd-BCO 两种不同材料超导块材的悬浮性能,结果发现GdBCO 的悬浮力在强磁场环境中表现出更大的潜力.这为高温超导磁浮在强磁场中的应用奠定了基础,通过更加合理地调节磁场的分布,可以更好地发挥高温超导块材的悬浮性能潜力 相似文献
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Effective method to control the levitation force and levitation height in a superconducting maglev system 下载免费PDF全文
《中国物理 B》2015,(11)
The influence of the width of the middle magnet in the permanent magnet guideways(PMGs) on the levitation force and the levitation height of single-domain yttrium barium copper oxide(YBCO) bulks has been investigated at 77 K under the zero field cooled(ZFC) state. It is found that the largest levitation force can be obtained in the system with the width of the middle magnet of the PMG equal to the size of the YBCO bulk when the gap between the YBCO bulk and PMG is small.Both larger levitation force and higher levitation height can be obtained in the system with the width of the middle magnet of the PMG larger than the size of the YBCO bulk. The stiffness of the levitation force between the PMG and the YBCO bulk is higher in the system with a smaller width of the middle magnet in the PMG. These results provide an effective way to control the levitation force and the levitation height for the superconducting maglev design and applications. 相似文献
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Jun Zhou Xing-Yi Zhang You-He Zhou 《Physica C: Superconductivity and its Applications》2010,470(5-6):336-339
Using a modified Gifford–McMahon refrigerator to cool the cylindrical bulk YBaCuO superconductor within the region of 100–10 K, and using an updated high-temperature superconductor (HTS) maglev measurement system, the levitation force and its time relaxation at different temperatures between a YBaCuO bulk superconductor and a permanent magnet (PM) have been measured under zero-field cooling. It is found that decrease the cooling temperature of HTS can decrease the hysteresis of magnetization and increase the maximum levitation force of each hysteresis loop. For the relaxation of levitation force, if the temperature is continually lowered to 10 K after the relaxation measurement at given cooling temperature is performed for 600 s, the levitation force will continue to decrease sharply with the lowering of temperature even though it will get stable if the temperature is not lowered. Our results shown in this work are a benefit to the understanding of levitation systems. 相似文献
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The results of the experimental and theoretical investigations of the magnetic levitation force appearing at the interaction of the multilayer superconducting block of the YBa2Cu3O7?x melted textured ceramic and a permanent magnet are presented. The maximum repulsive force and maximum attractive force are determined as functions of the thickness of the superconducting block in the superconductor cooling regime in both zero and nonzero magnetic fields. The dependence of the levitation force on the geometric parameters and critical current of the superconductor is found. 相似文献
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Marco A. B. Andrade Nicolás Pérez Julio C. Adamowski 《Brazilian Journal of Physics》2018,48(2):190-213
Acoustic levitation uses acoustic radiation forces to counteract gravity and suspend objects in mid-air. Although acoustic levitation was first demonstrated almost a century ago, for a long time, it was limited to objects much smaller than the acoustic wavelength levitating at fixed positions in space. Recent advances in acoustic levitation now allow not only suspending but also rotating and translating objects in three dimensions. Acoustic levitation is also no longer restricted to small objects and can now be employed to levitate objects larger than the acoustic wavelength. This article reviews the progress of acoustic levitation, focusing on the working mechanism of different types of acoustic levitation devices developed to date. We start with a brief review of the theory. Then, we review the acoustic levitation methods to suspend objects at fixed positions, followed by the techniques that allow the manipulation of objects. Finally, we present a brief summary and offer some future perspectives for acoustic levitation. 相似文献
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《Current Applied Physics》2003,3(4):367-376
Using hybrid magnets for fields up to 31 T, superconducting magnets up to 20 T and cryogen-free magnets up to 15 T, characterization of superconductors, materials synthesis and condensed matter physics are being done in the High Field Laboratory for Superconducting Materials. We have developed thin strong superconducting wire, which enable us to construct compact magnet, cryogen-free magnet and cryogen-free hybrid magnet for the first time. We have found that polymer materials, high Tc superconductors and protein single crystals synthesized in high magnetic fields show different characters from those synthesized in normal condition. Magnetic levitation is performed to make a microgravity condition for materials processing similar to the space. 相似文献
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利用一般电磁悬浮熔炼感应器,球形试样悬浮情况下,悬浮力和悬浮试样输入功率表达式,建立了不含悬浮感应器电流的悬浮试样输入功率表达式.利用这些表达式,结合自然对流情况下,球形试样在气体介质中的功率耗散模型,建立了悬浮熔炼工艺参量与悬浮熔炼试样温度之间的关系.以(TbDy)Fe2合金在Ar气保护情况下,在一定工艺条件下的电磁悬浮熔炼为例,得到了电磁悬浮熔炼各种工艺参量与悬浮试样温度的关系.通过对计算结果的分析,结合实际电磁悬浮熔炼特点,得到了降低电磁悬浮熔炼试样最低温度的措施:减小悬浮试样的半径;在能够实现悬浮
关键词:
电磁悬浮熔炼
悬浮力
输入功率
耗散功率 相似文献
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基于磁滞效应的YBCO块材磁刚度测试方法 总被引:1,自引:1,他引:0
处于外磁场中的高温超导块材具有自稳定性。这种特性使得高温超导块材在磁悬浮轴承、飞轮储能、磁悬浮列车等方面,具有潜在的应用价值。非理想高温超导体具有很强的磁通钉扎特性,表现出很强的磁滞性。处于悬浮状态的高稳超导体,其稳定特性与其悬浮刚度密不可分。文中首先描述了高温超导块材磁悬浮测试系统磁刚度测试原理。此刚度测试方法充分考虑了非理想高温超导块材磁滞效应对磁刚度的影响。基于这种测试方法,研究了YBCO块材在永磁轨道上方悬浮力刚度的特性。通过与传统刚度测试方法比较,这种方法更能反应高温超导磁悬浮车实际磁刚度特性。 相似文献
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本文研制的三维磁力测试夹具和三维霍耳探头,可以实现:1)直接测量出磁体与磁体、磁体与超导体等之间的三维磁力随两者之间相对位置的变化规律;2)直接测量出任何磁体或组合磁体在空间的三维磁场分布;3)通过将三个三维霍尔探头或九个单独的霍尔探头分别按研究内容的需要固定在所要研究的空间区域,再改变磁体与磁体之间、或磁体与超导体等之间的相对位置,从而在测量出它们之间的相互作用力的同时,测量出由于它们之间因相对位置改变而引起的动态磁场分布变化;还可以得到磁体接近超导体时磁场进入超导体的动态变化规律等.该套测试装置,将工作效率提高到原来的300%以上.这对研究磁性材料的宏观磁性质具有非常重要的意义. 相似文献
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通过对空心圆柱形永磁体与单畴GdBCO超导体磁悬浮力的实验测量,研究了空心圆柱形永磁体内径(d)的变化对超导体磁悬浮力的影响.结果发现,当空心圆柱形永磁体内径从0 mm增加到26 mm时,超导磁悬浮力大小与空心圆柱形永磁体内径有着密切关系(最小测量间距Z=2 mm),所有超导磁悬浮力曲线都存在磁滞现象.随着空心圆柱形永磁体内径的增大,最小间距处超导磁悬浮力逐渐减小,从d=0 mm时的14.8 N减小为d=26 mm时的-0.1 N,d≥20 mm时,最小间距处超导磁悬浮力出现负值;当0 mm≤d5 mm时,超导体最大磁悬浮力出现在最小间距处,d≥5 mm时,超导磁悬浮力先增大后减小,最大超导磁悬浮力产生的位置随着内径的增大而变大.研究表明:只有科学合理地设计永磁体结构参数,才能获得较大的磁场强度,提高超导磁悬浮力特性.该结果对设计并优化磁悬浮轴承系统、环形轨道和超导体的实际应用具有一定的指导意义. 相似文献