Based On Sextupole’s Multipole Eletromagnetic Propulsion System’s Launching Performan Improvement

Electromagnetic propulsion (EMP) is a technology which makes use of electromagnetic force to meet emission requirements by promoting projectile to a high velocity. This technology has several advantages, including wide range of projectiles’mass, high muzzle speed, high emission efficiency, clean energy and low cost of emission. Thus, EMP is applied widely in areas of aerospace, military and civilian. According to their propulsion principle and structure, EMPs can be divided into three types:coilgun, reconnection gun and railgun. Although the researches about these three types of EMP are aboundant, some technical defects have not been settled.To solve some technical defects, our research group has proposed multipole field electromagnetic configuration. The configuration owes several advantages:its axial accelerating force is greater than the radial compressive force, there is no contact between the armature and coil, and it is suitable for massive projectile launch. Compared with other EMPs, multipole field electromagnetic propulsion (MFEP) can realize spin speed controlled through adjusting the angle of the upper and lower coil. However, many mechanisms about MFEP still need further research due to its novelty. Against the shortages of MFEP, this dissertation will improve on the launching performance from the system itself and the external circuit.First, this dissertation analyzed MFEP’s magnetic diffusion, eddy current field and lumped parameter properties, and then researched MFEP’s dynamic properties, which provide theoretical support for simulation and experiment. Then,3D transient model of MFEP was built with finite element simulation software. The simulation found that the capacitor and voltage of pulse power, the size of driving coils, the initial position and coupling gap have a relatively large influence on muzzle speed, and thus have the optimal parameters match under certain constraints. And then analysis the impact of the discharge freewheeling ways and soft magnetic materials’magnetization to MFEP’s launching performance. Finding that appropriate size of discharge resistor and capacitor can accelerate the release of driving coils’ remaining current, weaken armature capture effect and improve emission efficiency. After adding soft magnetic material to the device, it can improve MFEP’s emission efficiency. The emission efficiency without soft magnetic material is 1.26%, and the emission efficiency when adding a soft magnetic material 7.5*Steell010 is 2.59%, efficiency doubled. Then compared the ordinary MFEP’s launching performance with the arc one, the result shows the arc is more suitable for armature rotation at high coupling, and can make the armature owing the same high muzzle velocity. The armature can realize positve and negative rotation through twisty the next driving coil, which improves rotation stability. Finally, this dissertation researched the feasiblity of MFEP’s double armature launch. And designed a single stage sixupole feild electromagnetic Propeller. The feasibility of double armature launch was verified through the analysis of theory, simulation and experiment. In the case of 8kV, alone on small armature emission efficiency is 2.50%, alone on the armature emission efficiency is 2.37%, at the same time, the efficiency of the two armatures launched is 4.27%, total emission efficiency improved significantly.