Optimization And Experimental Studies On Multipole Electromagnetic Launch System

Electromagnetic launcher (EML) uses electromagnetic force to accelerate projectile to a certain velocity. This technology has several advantages, including high muzzle speed, wide range of projectiles’mass, high energy conversion efficiency and inexpensive energy source. Thus, EML technology has extensive application potential in new weapon, nuclear engineering, aircraft carrier catapult, civil transportation and other fields. According to the different structure, conventional EMLs can be divided into railgun, coilgun and reconnection gun. The researches about these three types of EML are abundant, and some of their inherent defects were found:for a coilgun, its axial thrust force is much smaller than the radial compressive force and the conventional reconnection gun is mainly designed to launch tabular projectiles.To free from the defects mentioned above, our research group has proposed a new type of induction launcher that can produce radial magnetic field, which is called multipole field electromagnetic launcher (MFEL). It improves the structure of traditional EML and provides a better launch performance in some aspects. However, the researches about MFEL are insufficient due to its novelty. Some of MFEL’s mechanism are unclear and lack of experimental support. Therefore, this dissertation analyzed MFEL’s characteristics in details, proposed optimization method and finally verified its feasibility.First, this dissertation analyzed MFEL’s electromagnetic properties from the magnetic diffusion, eddy current field, lumped parameter and other perspectives, providing a theoretical basis for simulation and experimental works. Then,3D static and transient finite element models of MFEL were built and several types of connection pattern were proposed. Simulation results show the connection pattern with reverse current direction in adjacent coils has the best launch performance. The initial position of projectile, the gap between the projectile and the driving coils and the external circuit parameters have a relatively large influence on muzzle speed and thus have optimized values under certain constraints. In order to enhance the magnetic coupling between driving coils and the projectile, the arc and slot twisty configurations of MFEL were proposed. Three stage twisty MFEL transient models were built and compared with the conventional model. It is shown that the arc and slot configurations have a better energy conversion efficacy:the arc configuration can provide a larger axial thrust force and therefore has a higher linear muzzle velocity; the slot configuration can provide a larger torque so the rotate muzzle velocity is higher. In addition, with increasing twisty angle, the linear muzzle velocity of projectile will decrease gradually; the rotate muzzle velocity will first increase and then decrease. Finally, a single stage sextupole field electromagnetic launcher and the relevant experimental platform were designed and built. Launching experiments with different parameters were carried out to verify the feasibility of MFEL. Powered by a200uF capacitor bank charged to3000V, the launcher is able to accelerate a50.4g aluminum projectile to a velocity of15.4m/s.