“…After the raw sample is grown, the sample may be cut in different geometries with intended surface area aligned along the grain. The largest measured levitation stiffness occurs when the magnetic vector field is perpendicular to the copper planes, with a monotonic reduction of levitation force as the magnetic field becomes parallel with the copper planes [34][35][36] . The hysteresis gap is also observed to be largest when the copper planes are perpendicular to the applied field.…”
Flux-pinned interfaces maintain a passively stable equilibrium between two spacecraft in close-proximity.Although flux-pinning physics has been studied from a materials-science perspective and at the systems level, the sensitivities and implications of system-level designs on the dynamics need to be better understood, especially in interfaces with multiple magnets and superconductors. These interfaces have highly nonlinear, coupled dynamics that are influenced by physical parameters including strength of magnetic field sources, field-cooled position, and superconductor geometry.Kordyuk's frozen image model successfully approximates the characteristics of flux pinning dynamics but could provide more precise state prediction with the addition of these physical parameter refinements. This paper addresses that gap by offering parametric terms to improve the dynamics model, which may better simulate the behavior of a multiple-magnetmultiple-superconductor interface. The sensitivity of the general flux-pinned dynamics model is studied by varying the physical parameters and simulating the systems level dynamics. This work represents a critical step in the development of a model suited to spacecraft performance verification.
“…After the raw sample is grown, the sample may be cut in different geometries with intended surface area aligned along the grain. The largest measured levitation stiffness occurs when the magnetic vector field is perpendicular to the copper planes, with a monotonic reduction of levitation force as the magnetic field becomes parallel with the copper planes [34][35][36] . The hysteresis gap is also observed to be largest when the copper planes are perpendicular to the applied field.…”
Flux-pinned interfaces maintain a passively stable equilibrium between two spacecraft in close-proximity.Although flux-pinning physics has been studied from a materials-science perspective and at the systems level, the sensitivities and implications of system-level designs on the dynamics need to be better understood, especially in interfaces with multiple magnets and superconductors. These interfaces have highly nonlinear, coupled dynamics that are influenced by physical parameters including strength of magnetic field sources, field-cooled position, and superconductor geometry.Kordyuk's frozen image model successfully approximates the characteristics of flux pinning dynamics but could provide more precise state prediction with the addition of these physical parameter refinements. This paper addresses that gap by offering parametric terms to improve the dynamics model, which may better simulate the behavior of a multiple-magnetmultiple-superconductor interface. The sensitivity of the general flux-pinned dynamics model is studied by varying the physical parameters and simulating the systems level dynamics. This work represents a critical step in the development of a model suited to spacecraft performance verification.
“…Since the anisotropy in superconductor and matching field effect, critical current density in the ab plane is larger than that in ac or bc plane. 27 Therefore, it can be deduced that superconducting performance of sample B is the best, because single domain can relieve the effect of weak links in superconductor as much as possible and improve carrying current density. Figure 4. (a) Metallograph of sample A, (b) metallograph of sample B, and (c) metallograph of sample C.…”
Section: Fundamental Tribological Experiments Of Novel Superconductinmentioning
Novel superconducting tilting pad bearing can realize the compound of superconducting magnetic force and hydrodynamic fluid-film force in liquid rocket engine and possesses the advantages of larger bearing capacity and higher stiffness. The indispensable small operational clearance for the bearing would possibly cause rubbing phenomena between superconducting stator and magnet rotor under impact loads. Three Y1.8Ba2.4Cu3.4Ox bulk superconductors with different crystal domains are used to study the dry friction coefficients between superconductor and neodymium iron boron (NdFeB) magnet with nickel coating. In order to improve the fundamental tribological performance of the novel bearing, upper surface of modified superconducting tilting pad is covered by thin impregnated graphite and the nickel coating of magnet is replaced by chromium coating. Pin-on-disc experimental results indicate that the antifriction design method is effective and safe for liquid rocket engine. This study can promote the application process of novel superconducting bearing in a new generation of liquid rocket engine in China.
“…[7][8][9][10][11][12][13] In addition, it has been found experimentally that the angle between the magnetization direction of the PM and the c axis of the HTS significantly affects the levitation properties. [14][15][16][17][18] In fact, the magnetization direction of the PM does not often coincide with the c axis of the HTS in many practical applications.…”
The interaction between a permanent magnet (PM) assumed as a magnetic dipole and a flat high-temperature superconductor (HTS) is calculated by the advanced frozen-image model. When the dipole vertically moves above the semi-infinite HTS, the general analytical expression of vertical force and that of torque are obtained for an arbitrary angle between the magnetization direction of the PM and the c axis of the HTS. The variations of the force and torque are analyzed for angle and vertical movements in both zero-field cooling (ZFC) condition and field cooling (FC) condition. It is found that the maximum vertical repulsive or attractive force has the positive or negative cosine relation with the angle. However, the maximum torque has the positive or negative sine relation. From the viewpoint of the rotational equilibrium, the orientation of the magnetic dipole with zero angle is deemed to be an unstable equilibrium point in ZFC, but the same orientation is considered as a stable equilibrium point in FC. In addition, both of the variation cycles of the maximum force and torque with the angle are π.
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