Search

When armature passes through the central plane of a driving coil in the process of reluctance coil launching, the magnetic force will reverse and slow down the armature speed. To overcome this problem, the principle of reluctance coil launcher is analyzed. Meanwhile, this paper establishes a finite element analysis model to calculate the electromagnetic force, velocity, displacement and other parameters of the armature while the reluctance coil launcher works. Based on the simulation results, dynamic characteristics of the reluctance coil launcher are summarized and two methods for reverse force suppression are discussed. Furthermore, an experiment system is established and some experiments are carried out. This research concludes that resistor consumption method can effectively restrain the generation of reverse force, with no obvious bad impact on other performance, which provides a practical approach to achieving higher speed and efficiency for reluctance electromagnetic launcher.

Unmanned aerial vehicles (UAVs) have great advantages in maneuverability, economical efficiency, flexible flight and low environmental requirements. While the electromagnetic launch technology has great advantages in controllable launch, accurate armature velocity, clean energy and low recoil. Combining the advantages of the UAV and electromagnetic launch technology, an UAV-Launcher system based on electromagnetic launch is proposed. This article introduces the basic principle, working process and application advantages of that launcher, and key technologies in the UAV-launcher system process are analyzed It provides new ideas for the extended research and innovative application of UAVs and electromagnetic launchers.

The tanks and armor vehicles can be damaged by high-speed metal jet caused by the High Explosive Anti-Tank (HEAT). In order to improve the effective length and the penetration capacity of the metal jet, the electromagnetic enhancing system for the metal jet is put forward. Aiming to the effect of the time sequence to the performance of the metal jet, the relationship between the times of the high-speed metal jet and the strong pulsed magnetic field is analyzed, and then a numerical simulation model is established based on the Transient Magnetic Solver. After that the validity of the electromagnetic enhancing system for high-speed metal jet is verified, and the distribution characteristics of the magnetic field and the current density are obtained. It can draw the conclusion that the high-speed metal jet can become deformed with the effect of the axial pulsed magnetic field. And then the high-speed metal jet cannot be put off by the stretching force caused by the uneven velocity distribution. Furthermore, the radius of metal jet may become more even and the effective length will be extended. Meanwhile, the best delay time is to make the peak point of the discharge current just coincide with the time when the center sections of the metal jet and the magnetic field coil are consistent.

The effective treatment of the industrial wastewater is very significant to the protection of our environment. The system of wastewater treatment based on pulsed discharge plasma provides a new way for the disposal of industrial wastewater. However, the traditional reactor cannot meet the demand of degradation rate and the treatment efficiency. In order to improve the degradation rate and disposal efficiency of the wastewater, a solid-liquid-gas (SLG) three-state reactor for the high voltage pulsed discharge plasma system is put forward, and then the working principle of the reactor is introduced. Furthermore, a simulation model of the reactor is built. After that the electric field distribution of the SLG reactor is analyzed by numerical simulation. The contrast between the traditional reactor and the SLG reactor is carried out. Furthermore, the effect of the voltage and the diameter of the solid ball in the reactor are analyzed. It can be seen from the results of the analysis that the SLG reactor of the wastewater treatment system based on the high voltage pulsed discharge plasma has better effect than two-state reactors. The conclusion that the discharge voltage has great effect on the disposal efficiency can also be drawn. Meanwhile, the diameter of the solid packing can affect the distribution of the electric field. The research results are very important to the application of the SLG reactor in the wastewater treatment system.

The essential launching characteristics of four typical electromagnetic railguns models were comparatively reviewed referring to the current distribution in conductors. Such four models were as a small conductive simple railgun, the large resistive simple one, the large conductive simple one, and the large conductive complex one. First, according to strict physical theories, a small conductive copper-and-aluminum simple railgun and the proportionally-enlarged large simple railgun with deliberately-designed resistive materials could satisfy the same equations, the similar forms of current distributions, the same temperatures distributions at the corresponding positions, and the same launch velocity, etc. The small model can absolutely express the large one and vice versa. Second, the large resistive simple railgun and a conductive copper-and-aluminum simple railgun with the same structures could launch approximate projectiles to the same velocity, with the same temperature distribution on the surfaces at the corresponding positions. On the one hand, the large conductive approximate railgun is a little excellent than the large resistive one because of the less Ohmic loss; on the other hand, the resistive one has merely a little higher induction gradient than the conductive one. Third, the large conductive simple railgun carried a mal-distributed current and had a limited launching ability, while, the large conductive complex railgun carried a much evenly-distributed current and had a more powerful launching ability. The conclusions reached were: according to the large resistive simple model as a key reference lever, the small conductive simple railgun was an economic experimental facility to research the launching characteristics of both small and large conductive railguns; the large conductive complex model was a practical railgun model deserving investments for research.

As a kind of new concept kinetic weapons with hypervelocity, the electromagnetic railgun has a control technology on the sliding electrical contact between armature/rails. The initial sliding electrical contact belongs to the solid-solid dry friction state, which has a serious impact on the system launch efficiency and the rail life. This paper analyzes the research progress of liquid lubricated and solid lubricated technologies commonly used in the sliding contact of electromagnetic railgun in the initial launch stage. The application of hydrodynamic lubrication technique to electromagnetic railgun was discussed from the aspects of theory basis, preparation process, electro-thermal characteristics, mechanical properties and chemical properties. Finally, the application of low melting point alloy coating to improve the initial sliding contact of electromagnetic railgun was put forward. This article has important significance to the research of electromagnetic railgun technology.