Simulation analysis on interface thermal characteristic between rail and armature for electromagnetic railgun

摘要

The interface thermal characteristic between rail and armature affects significantly the launch performance of electromagnetic railgun. In this paper, the friction coefficient f between brass and aluminum is discussed; it is found that under hypervelocity and electrical contact condition, f maintains an order of magnitude with 10⁻², which is smaller than that under normal conditions. A further simulation model is developed to demonstrate concretely the order of magnitude of f when armature was launching in bore. Then, according to simulation results of interface temperature distribution, the thermal effect on armature wear and contact performance was analyzed. For an electromagnetic railgun with hypervelocity and high current, it is concluded that the heat on rail and armature interface mostly comes from friction, which can cause armature surface to melt and wear. The aluminum film is benefit for the contact performance as armature sliding.