The Research On Rotation Characteristics Of Multipole Field Electromagnetic Propulsion System

Electromagnetic launching(EML)is essentially technology in which the thrust force produced by the interaction of the electricity and magnetism accelerates the projectile to a predetermined speed.This technology has many advantages,including low cost,high efficiency,fast export speed,clean energy,the mass of the propelling object can be adjusted in a wide range,etc.It has broad application prospects in new weapons,aerospace,high-speed transportation and other fields.Since the different working principle and model structure,electromagnetic launchers can be roughly divided into three types: guideway type,coil type and reconnection type.Although these types have their own advantages,they also have some inherent defects,such as the direct electrical contact of the guide rail type could lead to serious ablation and wear;the radial compression force of the coil type is greater than the axial thrust force;and the shape of the reconnected projectile armature is limited.Aiming at the technical shortcomings of the above launchers,a multipole field electromagnetic launcher(MFEL),based on the idea of electromagnetic force generated by the interaction of radial magnetic field and circumferential current,is proposed by our laboratory team.The structure of MFEL not only improves some drawbacks of traditional EML in a certain extent,but also has unique spin stability characteristics.In the aspect of spin-stabilized launch,the current research mainly focuses on the multi-stage torsional structure.The main drawbacks of this mode are low efficiency and complex structure.Based on the existing problems,a new type of double layer saddle multipole field electromagnetic propulsion structure is proposed in this paper,and the computational simulation and experimental research are carried out.Firstly,the electromagnetic characteristics of MFEL were analyzed theoretically.Secondly,the model of conventional single-stage MFEL was constructed by simulation software,and the variable factors affecting the propulsion performance were analyzed and optimized.Then,the eddy current distribution on different armature structures was discussed concretely based on the result that the rotating effect of the torsional multistage MFEL is unsatisfactory,the single-stage saddle sextupole field electromagnetic launcher(SSFEL)configuration was built,the influence of several parameters including vertical slot' number,depth,width and different torsion angle on the rotational performance of SSFEL was analyzed.The simulation results show that the SSFEL has better rotating effect than the torsional multistage MFEL,but SSFEL reduces the linear exported velocity and the energy conversion efficiency of the system is not high.Then,a single-stage two-armature electromagnetic propulsion model is established and simulated.It is found that the energy conversion efficiency of the model is improved slightly.Therefore,a novel single-stage double layer saddle multipole field electromagnetic launcher(SSDFEL)was proposed,the rotational characteristic of SSDFEL was analyzed from the two aspects of eddy current distribution and force.The results show that the SSDFEL can significantly improve the energy conversion efficiency and greatly raise exported velocity and rotation speed of armature.Finally,a single-stage double layer saddle multipole field electromagnetic launcher was designed and manufactured.The experimental results are in agreement with the simulation results,which verify the feasibility and superiority of the launcher.