Study of Various C-Shaped Armatures in Electromagnetic Launcher

摘要

The current density distribution on the cross section of the rails is affected by the geometry and dimensions of the rails and armature. This paper analyzed a rectangular railgun that is formed by two parallel rails and an armature with various geometries. Rail thickness (w(r)), width (h(r)), and separation (s(r)) between two rails are equal to 2 cm, 4 cm and 4 cm, respectively. C-shaped armatures have three corners that are named front, back and arm side of armature which rounded step by step. All case studies simulated with the Finite Element Method Three Dimensions (FEM3D). For all steps, the inductance gradient, normal force, current density (J) distribution and maximum values of J are computed. The force between rails and armature named normal force. This force and pressure can be changed the rails and armature form. Friction force is increasing with increasing normal force. Maximum current densities occur at the armature corners and contact section between the rails and armature. These phenomena can produce a hot point that fuse the railgun and must be considered in armature and rail designing. This paper investigates the effect of armature geometry and dimensions on current density distribution, maximum value of current density, inductance gradient and normal force or normal pressure on armature.