Abstract:A railgun is a kind of new-concept kinetic energy weapon. To overcome the local aggregation of the high pulse current on the surface of the railgun conductor, a method was introduced to abate the skin effect. On the basis of theoretical analysis, three kinds of methods were adopted to increase the current uniformity coefficient. Then, the copper strips, whose thicknesses were 40, 20, 15, and 10 mm, respectively, were simulated with a typical half-period sine waveform that had a 10-ms pulsewidth and a 2-MA peak… Show more
“…In spite of that increasing the thickness can lead to the rise of the electromagnetic force, this rising has a slower trend. It is not recommended to increase the thickness excessively, otherwise the skin effect will become obvious and the loss will be enlarged (Xing et al 2015). Fig.…”
Section: Numerical Calculation and Simulation Studymentioning
The modified flux-coupling-type superconducting fault current (SFCL) is a high-efficient electrical auxiliary device, whose basic function is to suppress the short-circuit current by controlling the magnetic path through a high-speed switch. In this paper, the high-speed switch is based on electromagnetic repulsion mechanism, and its conceptual design is carried out to promote the application of the modified SFCL. Regarding that the switch which is consisting of a mobile copper disc, two fixed opening and closing coils, the computational method for the electromagnetic force is discussed, and also the dynamic mathematical model including circuit equation, magnetic field equation as well as mechanical motion equation is theoretically deduced. According to the mathematical modeling and calculation of characteristic parameters, a feasible design scheme is presented, and the high-speed switch’s response time can be less than 0.5 ms. For that the modified SFCL is equipped with this high-speed switch, the SFCL’s application in a 10 kV micro-grid system with multiple renewable energy sources are assessed in the MATLAB software. The simulations are well able to affirm the SFCL’s performance behaviors.
“…In spite of that increasing the thickness can lead to the rise of the electromagnetic force, this rising has a slower trend. It is not recommended to increase the thickness excessively, otherwise the skin effect will become obvious and the loss will be enlarged (Xing et al 2015). Fig.…”
Section: Numerical Calculation and Simulation Studymentioning
The modified flux-coupling-type superconducting fault current (SFCL) is a high-efficient electrical auxiliary device, whose basic function is to suppress the short-circuit current by controlling the magnetic path through a high-speed switch. In this paper, the high-speed switch is based on electromagnetic repulsion mechanism, and its conceptual design is carried out to promote the application of the modified SFCL. Regarding that the switch which is consisting of a mobile copper disc, two fixed opening and closing coils, the computational method for the electromagnetic force is discussed, and also the dynamic mathematical model including circuit equation, magnetic field equation as well as mechanical motion equation is theoretically deduced. According to the mathematical modeling and calculation of characteristic parameters, a feasible design scheme is presented, and the high-speed switch’s response time can be less than 0.5 ms. For that the modified SFCL is equipped with this high-speed switch, the SFCL’s application in a 10 kV micro-grid system with multiple renewable energy sources are assessed in the MATLAB software. The simulations are well able to affirm the SFCL’s performance behaviors.
“…The device typically utilizes pulsed capacitor discharges for electrical energy input. The combination of pulsed high-current feed and the velocity skin effect (VSE) at high-speed motion can result in current densities in the conductor that are on the order of GA/m 2 [1][2][3]. This in turn produces localized high heat accumulation, forming metal interface damage [4][5][6] and affecting service life [7,8].…”
The armature and rail sizes of electromagnetic rail launcher vary greatly, and the refined 3D finite element computation occupies a large amount of physical memory. In order to enhance the economy of dynamic computation, this paper proposes an adaptive hexahedral mesh method based on mesh expansion, compression, and translation. In addition, split nodes are used on both sides of the contact surface, and interface conditions and frictional heat sources are constrained through point penalty function method to solve non-ideal sliding electrical contact problems. Comparative calculations with the same type of software and the same model are carried out, and the results calculated in this paper are consistent with the relevant results of MEAP3D. This paper also compares the EMRL calculation results of adaptive mesh model and constant mesh model to verify the reliability of the method. In addition, the C-type EMRLs are compared and analyzed. The results show that due to the influence of velocity skin effect, the dynamic inductance gradient of the rail gradually increases over time and is greater than the static value. The maximum difference between the two is 5.65% of the dynamic inductance gradient. The steel shell generates eddy currents, causing a decrease in armature velocity of 4.7 m/s under the small caliber launcher. The maximum eddy current density waveform of the shell exhibits two peaks. In the frictionless heat, the temperature of the armature is underestimated, and under the action of frictional heat, the trailing edge of the armature is ablated and melted.
“…E-mail: jylu2019@163.com National Key Laboratory of Electromagnetic Energy, Naval University of Engineering, Wuhan, Hubei, 86-027-6546-1888, China and distribution of the horizontal direction [6]. Xing et al used commercial software MAXWELL to confirm that multi-layer copper strip rail can reduce the current concentration caused by current skin effect [7]. Stefani et al used their own electromagnetic simulation software EMAP3D to study the reversed current flow at current falling edge, but it did not take the different contact state into consideration [8].…”
Section: Introductionmentioning
confidence: 99%
“…Xing et al . used commercial software MAXWELL to confirm that multi‐layer copper strip rail can reduce the current concentration caused by current skin effect [7]. Stefani et al .…”
In electromagnetic launcher, the pulsed current is concentrated by contact state, current skin effect (CSE) and velocity skin effect (VSE), and heat the material locally. It will lead to melt or degradation, reducing stability and service life of the launcher. In order to study the current distribution with all these various influences, a 3D transient current analysis model with dynamic conductivity assignment and contact layer is proposed in this paper. It is found that the short contact length in armature moving direction can make two peaks overlap caused by CSE and VSE, and VSE can disturb the current distribution in horizontal direction. When designing armatures, it is recommended that the contact length in the moving direction should be long enough during the entire launch process, so to isolate the two peaks, and that the central length of the armature tail should be longer than the lateral length, so to prevent the current from concentrating more at the lateral edge. These conclusions help the optimization of the launcher structure to reduce local damage caused by current concentration and extend service life.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
