Optimal design of the magnetic field of a high-speed response solenoid valve

2002 ◽  
Vol 129 (1-3) ◽  
pp. 555-558 ◽  
Author(s):  
G. Tao ◽  
H.Y. Chen ◽  
Y.Y. J ◽  
Z.B. He
2012 ◽  
Vol 721 ◽  
pp. 114-119 ◽  
Author(s):  
Yuta Enokizono ◽  
Takashi Todaka ◽  
Masato Enokizono

MR (Magnetic Rheological) fluid is a kind of functional fluid, which can be hardened by impressing magnetic flux. MR fluid has the high speed response to the external magnetic field and a big yield stress in comparison with the ferrofluid. In recent years, various devices utilizing MR fluid have been developed. Such developments are enabled with knowledge based on measured viscoelastic properties of MR fluid. However, precise measurement to obtain effect of the magnetic field on viscoelasticity is very difficult. The difficulty exists in generating a uniform magnetic field and evaluating the effective magnetic field. Accurate measurements become possible by solving these problems. In this paper, we propose a new magneto-viscoelasticity measurement system of MR fluid, which can generate a uniform magnetic field.


Author(s):  
Yingzi Chen ◽  
Zhiyuan Yang ◽  
Wenxiong Peng ◽  
Huaiqing Zhang

Magnetic pulse welding is a high-speed welding technology, which is suitable for welding light metal materials. In the magnetic pulse welding system, the field shaper can increase the service life of the coil and contribute to concentrating the magnetic field in the welding area. Therefore, optimizing the structure of the field shaper can effectively improve the efficiency of the system. This paper analyzed the influence of cross-sectional shape and inner angle of the field shaper on the ability of concentrating magnetic field via COMSOL software. The structural strength of various field shapers was also analyzed in ABAQUS. Simulation results show that the inner edge of the field shaper directly affects the deformation and welding effect of the tube. So, a new shape of field shaper was proposed and the experimental results prove that the new field shaper has better performance than the conventional field shaper.


IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 171184-171194
Author(s):  
Ya Huang ◽  
Li Jiang ◽  
Peng Fu ◽  
Zhengyi Huang ◽  
Xuesong Xu

1968 ◽  
Vol 2 (4) ◽  
pp. 633-652 ◽  
Author(s):  
Charlles F. Stebbins ◽  
George C. Vlases

The jump conditions across a transverse ionizing MHD shock wave, where the magnetic field is in the plane of the shock, are examined. The conservation laws, in conjunction with Maxwell's laws and the equation of state, yield three jump equations in four unknowns. To uniquely describe jumps across an ionizing wave requires an additional descriptive relationship. The theory of Kulikovskii & Lyubimov and, later, Chu, in which the internal structure of the shock itself supplies the missing relationship, is examined. In particular, Kulikovskii & Lyubimov show, for appropriate ratios of thermal to magnetic diffusivities, that for low-speed waves the magnetic field compression across the shock is unity and the jump equations reduce to the ordinary Rankine—Hugoniot relations. For high-speed shock waves, the magnetic field compression, B2/B1, equals the gas compression across the wave, p2/p1, and the jump equations become the magnetohydrodynamic shock jump relations. Furthermore, intermediate speed shocks induce magnetic field compressions between 1 and p2/p1. An experiment was performed in an inverse pinch where E behind the shock, the shock and piston velocities, and the magnetic field compression across the shock, were measured over a wide range of initial conditions and shock velocities in hydrogen. The jump relations were written with B2/B1 as a parameter and programmed into a digital computer. The program was written for real, equilibrium hydrogen. The program provided easy access to a unique solution of the jump equations for any B2/B1. The experiment tends to confirm the Kulikovskii—Lyubimov—Chu theory. Ordinary shock waves were observed at low speeds and near-MilD shocks were observed at high speeds. Further, the relation was verified for the plasma behind the shock for low-speed shock waves, and was verified to within experimental accuracy for the intermediate class of shock waves.


2020 ◽  
Vol 99 (1) ◽  
pp. 25s-38s
Author(s):  
JIANG YU ◽  
◽  
BO WANG ◽  
HONGTAO ZHANG ◽  
PENG HE ◽  
...  

The droplet transfer and voltage-current characteristics of gas metal arc welding (GMAW) in single-pulsed GMAW (single GMAW-P), plasma pulsed GMAW (plasma GMAW-P), and plasma-GMAW-P with a magnetic field were studied using the synchronous acquisition system of high-speed camera and electric signals. The results showed the plasma arc and magnetic field had a significant effect on the droplet transfer process. The indirect arc of the plasma and gas metal arc emerged in the pulse peak phase causing a shunt phenomenon of the GMAW current. The period of the indirect arc was increased under the action of the magnetic field. In hybrid plasma GMAW-P, when the GMAW current did not exceed 140 A, several pulsed one-drop free transfers occurred and the droplet transfer period decreased with the increase in the plasma welding current; when the GMAW current exceeded 140 A, and the plasma welding current was less than 180 A, spray transfer was formed. The droplet transfer transformed into a projected transfer when the plasma welding current increased to 180 A. In plasma-GMAW-P hybrid welding with a magnetic field, the magnetic field had a slight effect on the transfer period. When the GMAW current did not exceed 140 A, the droplet transfer was mainly repelled transfer. The detaching location was on the right side of the wire when the magnetic field current was less than 3 A. When the magnetic field current exceeded 3 A, it was below or on the left side of the wire. When the GMAW current exceeded 140 A and the magnetic field current was less than 5 A, spray transfer was formed, but the droplet transfer mode transformed into a projected transfer with a magnetic field current of 5 A.


2003 ◽  
Vol 21 (7) ◽  
pp. 1497-1507 ◽  
Author(s):  
K. Shiokawa ◽  
W. Baumjohann ◽  
G. Paschmann

Abstract. We have studied the occurrence characteristics of bi-directional electron pitch angle anisotropy (enhanced flux in field-aligned directions, F^ /F|| > 1.5) at energies of 0.1–30 keV using plasma and magnetic field data from the AMPTE/IRM satellite in the near-Earth plasma sheet. The occurrence rate increases in the tailward direction from XGSM = - 9 RE to - 19 RE . The occurrence rate is also enhanced in the midnight sector, and furthermore, whenever the elevation angle of the magnetic field is large while the magnetic field intensity is small, B ~ 15 nT. From these facts, we conclude that the bi-directional electrons in the central plasma sheet are produced mainly in the vicinity of the neutral sheet and that the contribution from ionospheric electrons is minor. A high occurrence is also found after earthward high-speed ion flows, suggesting Fermi-type field-aligned electron acceleration in the neutral sheet. Occurrence characteristics of bi-directional electrons in the plasma sheet boundary layer are also discussed.Key words. Magnetospheric physics (magnetospheric configuration and dynamics; magnetotail; plasma sheet)


Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1712
Author(s):  
Baihao Cai ◽  
Juan Fu ◽  
Yong Zhao ◽  
Fugang Chen ◽  
Yonghui Qin ◽  
...  

In this paper, the morphological characteristics of arc plasma and droplet transfer during the alternating magnetic field-assisted narrow gap groove laser-MIG (metal inert gas) hybrid welding process were investigated. The characteristics of arc plasma and droplet transfer, electron temperature, and density were analyzed using a high-speed camera and spectrum diagnosis. Our results revealed that the arc maintained a relatively stable state and rotated at a high speed to enhance the arc stiffness, and further improved the stability of the arc under the alternating magnetic field. The optimum magnetic field parameters in this experiment were B = 16 mT and f = 20 Hz, the electron temperature was 9893.6 K and the electron density was 0.99 × 1017 cm−3 near the bottom of the groove, which improved the temperature distribution inside the narrow gap groove and eliminated the lack of sidewall fusion defect. Compared to those without a magnetic field, the magnetic field could promote droplet transfer, the droplet diameter decreased by 17.6%, and the transition frequency increased by 23.5% (owing to the centrifugal force during droplet spinning and electromagnetic contraction force). The width of the weld bead was increased by 12.4% and the pores were also significantly reduced due to the stirring of the magnetic field on the molten pool.


2001 ◽  
Vol 183 ◽  
pp. 187-196
Author(s):  
D.W. Kurtz

AbstractThe rapidly oscillating Ap stars are magnetic peculiar A stars which pulsate in multiple p modes with periods in the range of about 6 to 16 minutes with their oscillation axes aligned with the oblique magnetic axes of the stars. Some of these stars have the richest frequency spectra of any non-degenerate stars other than the sun. This paper shows how photometric observations using small telescopes can be used to work on several astrophysically interesting problems posed by these stars. An example of high precision photometry is shown. The proof of oblique dipole pulsation, the distortion of pulsation modes (probably by the magnetic field), and the determination of asteroseismic luminosities are all discussed. The latter, especially when combined with new theoretical developments concerning magnetic field-pulsation interaction, suggests that Ap stars have lower effective temperatures and/or smaller radii than has been previously thought. It is pointed out that this may be related to the recently discovered extreme discrepancy in effective temperature determined from the wings and cores of the Hα line.


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