Spatial measurement in rotating magnetic field plasma acceleration method by using two-dimensional scanning instrument and thrust stand

2018 ◽  
Vol 89 (4) ◽  
pp. 043505 ◽  
Author(s):  
T. Furukawa ◽  
K. Takizawa ◽  
K. Yano ◽  
D. Kuwahara ◽  
S. Shinohara
2018 ◽  
Vol 846 ◽  
pp. 121-142 ◽  
Author(s):  
Mingfeng Qiu ◽  
Shahriar Afkhami ◽  
Ching-Yao Chen ◽  
James J. Feng

We use two-dimensional numerical simulation to study the interaction between a pair of ferrofluid drops suspended in a rotating uniform magnetic field. Numerical results show four distinct regimes over the range of parameters tested: independent spin, planetary motion, drop locking and direct coalescence. These are in qualitative agreement with experiments, and the transition between them can be understood from the competition between magnetophoretic forces and viscous drag. We further analyse in detail the planetary motion, i.e. the revolution of the drops around each other while each spins in phase with the external magnetic field. For drops, as opposed to solid microspheres, the interaction is dominated by viscous sweeping, a form of hydrodynamic interaction. Magnetic dipole–dipole interaction via mutual induction only plays a secondary role. This insight helps us explain novel features of the planetary revolution of the ferrofluid drops that cannot be explained by a dipole model, including the increase of the angular velocity of planetary motion with the rotational rate of the external field, and the attainment of a limit separation between the drops that is independent of the initial separation.


1970 ◽  
Vol 48 (15) ◽  
pp. 1806-1816 ◽  
Author(s):  
W. R. Datars

The galvanomagnetic properties of copper were studied by observing the torque induced in single-crystal copper by a slowly rotating magnetic field at 1.4 °K. The induced torque varied linearly with the speed of magnet rotation and quadratically with magnetic field. There was large induced torque in high-purity samples from the open orbits in both one-dimensional and two-dimensional regions. In a sample with low ωcτ, there was also a background torque. The induced torque is described by Falicov's solution of the boundary value problem for a sample sphere with a resistivity tensor. The open-orbit torque in an uncompensated metal such as copper is approximately proportional to the transverse resistivity component ρ11. The anisotropy of the open-orbit torques for the (100) and (110) planes of copper is in agreement with that calculated for the magnetoresistance from the Fermi surface of copper. There is anisotropy in the background torque with minima in the region of symmetry directions and for a rotation in a (100) plane.


2021 ◽  
Vol 2021 (2) ◽  
pp. 26-34
Author(s):  
O. Makarchuk ◽  
◽  
D. Calus ◽  
V. Moroz ◽  
◽  
...  

The purpose of the research under consideration is to develop a mathematical model to calculate the trajectories of the ferromagnetic operating elements (millstones) of an electromagnetic mill, moving in a rotating magnetic field under electrodynamic and hydrodynamic resistance forces being limited by the space of the mill’s working chamber. The millstone motion is described through the equations of plane motion of arbitrary-shaped two-dimensional body. The driving forces of this motion are determined on the basis of the approximation of the tabulated functions connecting the module and the orientation of the equivalent force applied to the millstone, with its position in the working chamber and composite MMF phase of mill inductor winding. These tabulated functions are derived from the estimation of the magnetic field inside a working chamber with millstones, in two-dimensional quasi-stationary approximation, using FEM analysis. The publication contains the approximation algorithm for these tabulated vector functions of a vector argument, mathematical statement of millstones trajectories calculating, and analysis of mathematical experiments results that make it possible to evaluate the adequacy of the model. The developed tool enables conducting quantitative analysis of grinding/mixing process and will help to establish relationships between the electromagnetic mill design parameters and its performance. References 21, figures 6.


AIP Advances ◽  
2017 ◽  
Vol 7 (11) ◽  
pp. 115204 ◽  
Author(s):  
T. Furukawa ◽  
K. Takizawa ◽  
D. Kuwahara ◽  
S. Shinohara

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