Background As an important branch of electromagnetic launch, multi-stage synchronous induction coil gun has become one of the hotspots of launch research because of its non-contact, linear propulsion and high efficiency. Among them, the armature outlet velocity is an important index, which is affected by many factors such as the structural parameters, material properties and coil circuit parameters. However, the existing research lacks theoretical analysis on various factors.

Purpose The purpose of this paper is to analyze theoretical approaches for improving the armature outlet velocity, and to explore the factors affecting it.

Methods Based on the equivalent circuit model, this paper derives the analytical formula of armature induced eddy current and investigates these factors affecting the outlet velocity via finite element simulation.

Results Theoretical analysis shows that reducing the total inductance of the coil-armature equivalent circuit can increase the armature outlet velocity. Simulation results show that under the same initial electrical energy, reducing the number of turns of coils, reducing the cross-sectional shape factor of the rectangular wire, increasing the thickness and length of armature, and reducing the line inductance can improve the armature outlet velocity. Considering various factors, the simulated outlet velocity of 32 kg armature driven by 5-stage coil can reach 202.1 m/s, and the launch efficiency is 33.3%. The influence of various factors on the armature is in line with the theoretical analysis results.

Conclusions The research content of this paper provides some theoretical support for the design of multi-stage synchronous induction coil gun scheme.