2019, Rudnev, Igor, Osipov, Maxim, Pokrovskii, Sergey, Podlivaev, Alexey, Руднев, Игорь Анатольевич, Осипов, Максим Андреевич, Покровский, Сергей Владимирович, Подливаев, Алексей Игоревич

For the development of levitation bearings and transportation systems based on coated conductor (CC) tapes it is important to know not only information on levitation force at vertical displacement, but also the data on stability of the system during lateral displacements of superconductor relative to permanent magnets. In this paper, we present new experimental results on investigation of both levitation and guidance forces of CC-tapes stacks subjected to cyclical lateral displacements relative to the position of permanent magnet. For the measurements we used 12 mm wide commercially available CC-tape manufactured by SuperOx. The long tape was cut into pieces 12 mm x 12 mm which then put to the stack. Total number of the single tape in the stack N was varied from 5 to 100. Under lateral displacement we measured the dependencies of levitation and guidance forces on value of displacement for various number of N and found that both levitation and guidance forces tend to decrease as a number of periodical cycles of displacements increase. The rate of reducing of forces was observed to depend on the number of tapes in the stack. We observed that dependencies of levitation and lateral forces on lateral displacements have a hysteresis. The area of hysteresis, which corresponds to the magnitude of energy losses, was found to decrease with increasing of number of elements in the stack. Experimental results are in a good agreement with the theoretical calculations of lateral force.

2021, Veselova, S., Osipov, M., Starikovskii, A., Anishenko, I., Pokrovskii, S., Abin, D., Rudnev, I., Веселова, Светлана Владимировна, Осипов, Максим Андреевич, Стариковский, Александр Сергеевич, Мартиросян, Ирина Валерьевна, Покровский, Сергей Владимирович, Абин, Дмитрий Александрович, Руднев, Игорь Анатольевич

© Published under licence by IOP Publishing Ltd.In this work, the phenomena of electromigration in samples of HTSC tapes of the 2nd generation was investigated. Samples of REBa2Cu3O7-x (REBCO, where RE is a rare earth element) were used in the form of a copper-plated tape. A superconducting bridge was preliminarily formed on the surface of the tape by the method of chemical etching (to decrease the total value of critical current). The sample was exposed by a direct current of I = 0.9Ic . The duration of exposure was up to 350 hours. The value of the current density in the area of the bridge was J = 1.38 1010A/m2. The measurements were carried out at liquid nitrogen temperature (77 K). The influence of the electric current flow on the value of the sample critical current is controlled at the selected time intervals. The experiment showed high stability of the tape under the specified conditions.

2021, Anishchenko, I. V., Osipov, M. A., Pokrovskii, S. V., Abin, D. A., Starikovskii, A. S., Rudnev, I. A., Мартиросян, Ирина Валерьевна, Осипов, Максим Андреевич, Покровский, Сергей Владимирович, Абин, Дмитрий Александрович, Стариковский, Александр Сергеевич, Руднев, Игорь Анатольевич

© 2021, Pleiades Publishing, Ltd.Abstract: Stacked composite high-temperature superconducting tapes (HTS tapes) are advanced material for development of magnetic levitation systems such as levitation transport, bearings, and kinetic energy storage. At use of superconductor in variable fields, energy losses owing to existence of heat in superconductor leading to decrease in critical current and, as a consequence, in the levitation force are inescapable. One of the key advantages of stacks of HTS tapes over traditional bulk HTS is the presence of a metal substrate and layers of silver and copper, which leads not only to high strength but also to suitable thermal conductivity of the stacks, which makes it possible to remove released heat efficiently. Investigation of mechanisms of control of thermal properties of the systems, as well as development of efficient methods of checkout of heat transfer parameters of the system at various rates of insertion of an external magnetic field, is a relevant objective. The results of calculation of the behavior of the stack of HTS tapes in an external magnetic field by the finite element method accomplished with use of the Comsol Multiphysics software package are presented in this work. Investigations of control of thermal properties of a levitation system are carried out, and also efficient methods of checkout of the parameters of heat transfer of the system at various rates of insertion of external magnetic field are developed. It is demonstrated that improvement of thermal and, as a consequence, levitation properties of the system can be achieved by the effect of both change in architecture of the stacks themselves and use of various configurations of the cryogenic cooling system. Various alternatives of implementation of the cryocooler cooling system and also various configurations of the stacks at liquid-nitrogen cooling are discussed. It is demonstrated that liquid nitrogen cooling is efficient so far as the change in temperature in the system is less than 3 K. In the case of liquidless cooling of the stack, the configuration with lateral cooling is optimal. The presence of a mechanical cooling passage in the form of a hole in the case of low rates of insertion of the magnetic field either leads to degradation of the system or does not have an effect on its properties. At increase in the rate of insertion of the external magnetic field, the presence of the mechanical cooling passage leads to increase in the maximum levitation force.

2022, Starikovskii, A., Osipov, M., Anishchenko, I., Abin, D., Pokrovskii, S., Rudnev, I., Осипов, Максим Андреевич, Мартиросян, Ирина Валерьевна, Абин, Дмитрий Александрович, Покровский, Сергей Владимирович, Руднев, Игорь Анатольевич

IEEEThis paper presents a study of the levitation system consisting of magnetized and non-magnetized HTS tape stacks. A comparison of such a system with the classical one, consisting of a stack of tapes and a permanent magnet, was carried out. The objects of the study were tapes manufactured by SuperOx, cut into 12 mm 12 mm fragments and formed into stacks with different height. Experimental data on the levitation force value at vertical and lateral displacements of a magnetized stack of HTS tapes and permanent magnets relative to the position of an ordinary tape stack were obtained. A simulation of the magnetic field distribution around a magnetized stack of 80 tapes and a permanent magnet was performed.

2019, Irina, Anischenko, Sergei, Pokrovskii, Igor, Rudnev, Osipov, Maxim, Мартиросян, Ирина Валерьевна, Покровский, Сергей Владимирович, Руднев, Игорь Анатольевич, Осипов, Максим Андреевич

In many levitation systems superconductors are used in combination with permanent magnets. In this paper we considered three types of magnetic assemblies that are most often used: with magnets oriented in one direction, oppositely oriented magnets and the Halbach array. Based on the H-formalism, we performed modeling of a magnetic field and levitation force in a system consisting of the high temperature superconductor (HTS) tape stack and the assembly of permanent magnets. It was shown that if a spatial distribution of a gradient magnetic field changes in height it is necessary to take into account the magnetic history of the superconductor. The proposed computational model includes a combination of scalar and vector potentials, as well as modeling the real movement of an HTS tape stack in a levitation system. The simulation results were verified by corresponding experiments. The proposed approach is universal for modeling levitation systems of complex configurations.

2021, Osipov, M., Anishenko, I., Starikovskii, A., Abin, D., Pokrovskii, S., Podlivaev, A., Rudnev, I., Осипов, Максим Андреевич, Мартиросян, Ирина Валерьевна, Стариковский, Александр Сергеевич, Абин, Дмитрий Александрович, Покровский, Сергей Владимирович, Подливаев, Алексей Игоревич, Руднев, Игорь Анатольевич

A new type of scalable high-temperature superconducting magnetic bearing is proposed. The bearing is based on the multilayer open windings made of coated conductor-tapes (CC-tapes). To demonstrate the possibility of manufacturing such a bearing construction we have built a working prototype and studied its characteristics. The manufactured model of bearing includes a stator, consisting of three multilayer rings (CC-tapes pancake coils) of 12 mm CC-tape and a composite rotor consisting of three rings of permanent magnets, each composed of 16 NdFeB 10 x 10 mm permanent magnets. We showed a contactless levitation of rotor relative to stator, as well as rotation of rotor and we measured load curves, namely the dependence of the rotor displacement on restoring force for axial and radial loads. Numerical simulation of bearing load characteristics has been carried out by the finite element method in the Comsol Multiphysics software. The calculation results are in a good agreement with the experimental data.

2022, Abin, D. A., Osipov, M. A., Starikovskii, A. S., Rudnev, I. A., Stolbunov, V. S., Kulevoy, T. V., Fedin, P. A., Абин, Дмитрий Александрович, Осипов, Максим Андреевич, Стариковский, Александр Сергеевич, Руднев, Игорь Анатольевич

2019, Osipov, M., Starikovskii, A., Abin, D., Pokrovskii, S., Anischenko, I., Rudnev, I., Осипов, Максим Андреевич, Стариковский, Александр Сергеевич, Абин, Дмитрий Александрович, Покровский, Сергей Владимирович, Мартиросян, Ирина Валерьевна, Руднев, Игорь Анатольевич

© 2019 International Institute of Refrigeration. All rights reserved. In our report, we present new results on investigation of the influence of temperature on the levitation force between the stacks of high temperature superconducting tapes (or coated conductor - CC tapes) and a permanent magnets. We studied the changing in value of levitation force at decreasing of temperature down to 30 K for field cooled (FC) and zero field cooled (ZFC) modes for various number of tape in the stack. In the measurements we used 12 mm wide commercially available CC-tape manufactured by SuperOx. The tapes were cut into pieces 12 mm x 12 mm. The number of layers in the stack ranged from 5 to 100. Cooling of the CC-tapes stack was carried out in cryo-free cryostat. Temperature range was from 30 to 80 K. Results showed that temperature has much influence on levitation force in ZFC mode whereas for FC mode the influence of temperature on levitation force is insignificant. The experimental data were compared with the results of calculations performed by using COMSOL Multiphysics. The obtained results are very useful for the practical application in magnetic levitation based systems.

2021, Osipov, M., Starikovskii, A., Anishchenko, I., Pokrovskii, S., Abin, D., Rudnev, I., Осипов, Максим Андреевич, Стариковский, Александр Сергеевич, Мартиросян, Ирина Валерьевна, Покровский, Сергей Владимирович, Абин, Дмитрий Александрович, Руднев, Игорь Анатольевич

© 2021 IOP Publishing Ltd.This article presents the study of the temperature effect on the levitation characteristics of stacks of CC-tapes from various manufacturers SuperOx, Theva and Sunam. Tapes differ in the values of the critical current density, architecture, and parameters of the metal substrate. Stacks of tapes were assembled from 12 by 12 mm square pieces of CC-tape. The number of elements in the stacks varied from 5 to 70. The dependences of the levitation force Fz (the vertical component of the force in the system permanent magnet - HTSC stack) on temperature were obtained both in zero field cooling (ZFC) and in field cooling (FC) modes. The measurements were carried out in the temperature range of 32-100 K. We have established that, down to the minimum operating temperatures, a decrease in temperature leads to a continuous increase in levitation force in ZFC mode. In FC mode, the Fz value tends to saturate after the initial increase in force. Cooling below the boiling point of liquid nitrogen up to 65 K gives a levitation force gain of 5%-10%. At the same time, cooling to 35 K gives an increase in levitation force by 7%-23%. It was found that an increase in the number of elements in the stack from 5 to 70 leads to an increase in the levitation force with a tendency to saturation for all temperatures studied. Excellent agreement between the experimental and calculated dependences of the levitation force on temperature and the number of elements in the stacks is demonstrated. Calculations show that for Sunam tapes, 90% of the levitation force is achieved with a stack thickness of 100 tapes at the boiling point of liquid nitrogen, and with 70 tapes at lower temperatures. The distributions of the magnetic field during the approach/removal of magnets, as well as the distribution of the trapped magnetic flux at different temperatures and numbers of elements in the stacks are modelled.

2022, Kaul, A. R., Chepikov, V. N., Mathon, O., Monteseguro, V., Menushenkov, A. P., Ivanov, A. A., Chernysheva, O. V., Rudnev, I. A., Osipov, M. A., Менушенков, Алексей Павлович, Иванов, Андрей Анатольевич, Чернышева, Ольга Викторовна, Руднев, Игорь Анатольевич, Осипов, Максим Андреевич

© 2022 IOP Publishing Ltd.We studied the effect of artificial pinning centers in the form of nanoinclusions of stannate BaSnO3 (BSO) and zirconate BaZrO3 (BZO) barium on the critical current of high-temperature superconducting tapes of the second generation (2G) based on YBa2Cu3O 7-δ films (YBCO). It has been found that the introduction of BaZrO3 nanoinclusions increases the critical current at 77 K for the magnetic field direction parallel and normal to the tape surface, while the introduction of BaSnO3 nanoinclusions decreases the critical current in both cases. To elucidate the origin of a different impact of nanoinclusions we examined the local structure of the YBCO-matrix using x-ray absorption spectroscopy (EXAFS and XANES). The spectra were collected at K-edges of Cu, Sn, and Zr at the European Synchrotron (ESRF). It was revealed that the introduction of BaZrO3 nanoinclusions increases the stiffness of copper-oxygen bonds in superconducting CuO2 plane and minimizes their static disorder in the YBCO matrix, while the introduction of BaSnO3 nanoinclusions leads to a significant increase in static disorder with a relatively weak effect on the stiffness of Cu-O bonds. These changes in the local structure become decisive for changing the macroscopic properties of high-temperature superconductor-tapes.