Numerical analyzing the electromagnetic launcher using FEM-3D in time domain

摘要

The Inductance, current density, Force, Pressure, and Electrical Resistance are essential quantities in railgun. These quantities are as function of bore dimension (h × s), rails thickness (w) and location of armature within the rails x(t). In this paper, the applied current pulse on the rails has the width 2.3 ms and peak amplitude 1kA. The electromagnetic launcher included copper rails and an aluminum armature. The copper rails are 20 mm × 20 mm wide and 470 mm long. The aluminum armature is 20 mm ×20 mm wide and 20 mm long. To calculate the applied vertical force between two rails, obtained by vector multiplying the current density with magnetic flux density, and then integrated over the rail value. The vertical pressure on the rails by the vertical force between two rails is computed by this force divided by area which this area found by multiplying the rail width (h) with location of armature within the rails. Internal inductance is calculated by the internal magnetic energy. To calculate the electrical resistance of the rails and armature, at first the voltage and current passing of the rails and armature are calculated, and then the Ohm''s law is used. The current distribution on the rails, the vertical force and vertical Pressure on the rails, internal inductance and electrical resistance of the rails and armature in the time domain are calculated and have been shown in the some figures.