3D Analysis on Distribution of Pulsed Current in Electromagnetic Launcher Considering Contact State and Movement

Abstract

In electromagnetic launcher, the pulsed current is concentrated by contact state, current skin effect (CSE) and velocity skin effect (VSE), and heat the material locally. It will lead to melt or degradation, reducing stability and service life of the launcher. In order to study the current distribution with all these various influences, a 3D transient current analysis model with dynamic conductivity assignment and contact layer is proposed in this paper. It is found that the short contact length in armature moving direction can make two peaks overlap caused by CSE and VSE, and VSE can disturb the current distribution in horizontal direction. When designing armatures, it is recommended that the contact length in the moving direction should be long enough during the entire launch process, so to isolate the two peaks, and that the central length of the armature tail should be longer than the lateral length, so to prevent the current from concentrating more at the lateral edge. These conclusions help the optimization of the launcher structure to reduce local damage caused by current concentration and extend service life.