Doğruer, M.; Abdioğlu, M.; Motoki, T.; Ozturk, U. Kemal

Abstract This study investigates the magnetic levitation and guidance characteristics of Ag-doped DyBa2Cu3O7-δ superconducting bulks, synthesized by the single-direction melt growth (SDMG) technique. The levitation force, vertical stiffness and lateral guidance force are measured at varying cooling heights (CHs) of 5 mm, 25 mm and 50 mm, with a constant working height (WH) of 5 mm for lateral force measurements. DyBa2Cu3O7-δ samples are cooled using liquid nitrogen (77 K) and thermal stabilization is achieved before force data collection. Results show that levitation forces increase with CH, while the levitation force curves exhibit both attractive and repulsive behavior depending on the CH. The lateral guidance force is higher for the Ag2 sample than for the Ag1 sample and decreased as the temperature decreased. Vertical stiffness also increased with CH and decreased as the levitation gap decreased, confirming heightened guidance forces at smaller distances. The flux density distributions, including both lateral ( B x ) and vertical ( B y ) components, are found to significantly impact the levitation and guidance force performance. Specifically, configurations with concentrated B x gradients improved levitation stability, while configurations with distributed B y led to stronger guidance forces. These findings underscore the importance of optimizing the PMG design to balance B x for levitation and B y for guidance in superconducting systems.

İncele

Ozturk, U.Kemal; Yıldız, Ali Suat; Abdioglu, Murat

This study aims to investigate the performance parameters of high-temperature superconducting (HTS) bulks and permanent magnets (PMs) as magnetic field sources in electrodynamic suspension (EDS) systems, with the goal of enhancing the currently low magnetic lift force and reducing the high drag force in such systems. A numerical analysis is conducted on an EDS system utilizing Halbach arrays of HTS and PM bulks. The H-formulation within the Partial Differential Equation (PDE) module is employed to simulate the flux-trapping performance of the HTS bulks, with results verified by experimental data from the literature. The lift and drag forces between the arrays and an aluminium rail are investigated using the Rotating Machinery-Magnetic module of COMSOL. It is observed that increasing the width of the central sample in the array results in a higher peak value of the vertical magnetic flux density and a broader peak profile, indicating a more extended effective magnetic field region across the rail surface. The HTS-based system exhibits significantly higher lift force and loading capacity compared to its PM-based counterpart. Specifically, a Halbach array composed of three HTS bulks (10 mm, 70 mm, 10 mm widths; HTS#10-70-10) achieves a better lift force representing a 211.5 % increase over the PM array. Furthermore, the lift-to-drag ratio (LDR) of the HTS array improves by 17.2 %. The results indicate that the HTS arrays offer superior performance in terms of both lift force and energy efficiency, highlighting their potential for enhancing the applicability of HTS-EDS systems in real-scale applications. This study features the advantages of HTS-based systems in achieving higher loading capacities and more efficient operation conditions compared to the PM arrays.

AtıfScopus1·WoS1·OpenAlex1

İncele

Öztürk, Ufuk Kemal; Abderrahmane, Babe Cheikh; Uzun, Oğuzhan; Abdioğlu, Murat; Güner, Sait Barış; Quéval, Loïc

This study introduces a novel Top-Interior Multi-Seeding Melt Growth (TI-MSMG) technique for fabricating high-performance YBCO bulk superconductors and explanations some physical background based on FEM modelling. The depth of the interior seed was gradually changed as 0, 2 and 4 mm (samples S0, S2 and S4, respectively) from the upper surface of the samples. By incorporating an interior seed into the precursor pellet, the TI-MSMG method enables systematic control over grain morphology and critical current density distribution. Magnetic levitation and guidance forces were measured using a three-axis force measurement system, and a two-dimensional finite element method (FEM) model based on the H-formulation of Maxwell’s equations was developed to simulate the electromagnetic behaviour of the superconductors with different seed positions. Experimental and modelling results reveal that samples incorporating an interior seed (S2) exhibit significantly enhanced levitation and guidance forces compared to S0 and S4, attributable to improved inter-domain interactions and morphological consistency, so a better current coupling. The numerical simulations accurately reproduced the experimental findings, confirming the validity of the modelling approach. These findings indicate that the TI-MSMG process not only addresses some limitations of conventional top-seeding methods but also enhances levitation force performance through optimization of interior seed depth, thereby enabling more efficient and tailored designs for high-temperature superconducting systems such as magnetic levitation, energy storage, and superconducting motors.

İncele

Abdioglu, Murat

MgB2 superconductors can be proposed as a good candidate for Maglev systems due to their superior structural and superconducting properties. Besides, magnetic levitation and guidance force properties of these superconductors should be increased for commercial applications of Maglev systems. Therefore, the critical current density and magnetic levitation and guidance force properties of MgTi0.06B2 superconducting samples were investigated in this study, at measurement temperatures of 20 K and 25 K, depending on benzil (C14H10O2) addition in different adding amounts of 0, 1.5, 3, 4.5, 6 and 9 wt%. In addition to benzil, nanometer-sized silver particles were added to the samples in a constant ratio of 2 wt% to enhance the structural properties. The maximum critical current density values increased from 67 kA/cm2 for pure sample to 92 kA/cm2 with benzil adding amount of 3 wt% at T = 20 K, indicating an increment of 37%. In addition, the levitation force in ZFC (zero field cooling) regime and the guidance force in FC (field cooling) regime at 20 K increased at an amount of 46% and 57%, respectively, with 3% benzil addition. It can be said that the suitable amount of benzil addition as a carbon source produces additional pinning centres inside the MgTi0.06B2 and thus structural properties, critical current density and therefore, magnetic levitation properties of the samples are increased.

AtıfScopus3·WoS3·OpenAlex3

İncele

Cansiz, Ahmet; Reisoglu, Ahmet F.; Ozturk, Kemal; Abdioglu, Murat

Levitation strength provided by high temperature superconductors are limited for device applications. Although superconducting material properties are continuously improving, there is still strong necessity of efficient design mechanisms for the superconducting magnetic levitation systems. Studies in the last decades have shown that combining multi-surface superconductor and permanent magnet components in optimum configurations has improved the levitation forces. In this respect, Halbach arraying permanent magnets interacting with multi-surface superconductors has become one of the most utilized methods. This paper investigates frozen image modeling of the levitation and guidance forces on a particular levitation system, which consists of a permanent magnet guideway and high temperature superconductor car body. The levitation enhancement is investigated for three configurations according to force interactions between the guideway and car body. These configurations are based on the use of single permanent magnet-single superconductor, Halbach array permanent magnets-single superconductor and Halbach array permanent magnets-multi-surface superconductors. The vertical and guidance forces for the present configurations were calculated in terms of field cooling and zero field cooling conditions by using frozen image model with magnetic dipole approximation. The predicted force calculations are analyzed in terms of vertical and lateral traverses of the car body respect to guideway for particular measurement distances. The force analysis provided by frozen image model qualitatively agree with the previously obtained experimental data.

AtıfScopus8·WoS9·OpenAlex9

İncele

Erdem, Ozge; Guner, Sait Baris; Celik, Sukru; Kucukomeroglu, Tayfur

This research presents the influence of pyrene (C16H10) addition (0, 2, 4, 6, 8, 10 wt%) on the superconducting properties of bulk MgB2. For C16H10 added MgB2 samples, a shrinkage in a-lattice parameters was determined, whereas c-lattice parameters remained practically unchanged. The (1 1 0) peak observed at 2θ ≈ 59.9◦ slightly shifted to higher angles, the lattice strain increased and the crystallite size reduced after C16H10 addition. By virtue of induced stronger pinning force, the in-field critical current density (Jc) increased after C16H10 addition. The Jc value at 20 K and 4 T was obtained about two times higher (8.54 × 103 A/cm2) for 4 wt% C16H10 added MgB2 sample than that of the pure one. In addition, the variation of levitation force characteristic of MgB2 with increasing C16H10 content was determined at 20, 25 and 30 K. The best vertical levitation force performance in zero-field-cooled regime was obtained as 7.09 N/g at 20 K for 4 wt% C16H10 added MgB2 sample with 13 mm in diameter.

AtıfScopus8·WoS6·OpenAlex8

İncele