Numerical modeling of melt-wave erosion in conductors [railgun armatures]

This paper presents two numerical approaches to modeling melt-wave erosion in conductors. The first uses a one-dimensional finite-difference formulation and provides a starting point for understanding the effects of applied field and material properties on erosion speed. The second approach involves manipulating material properties in the three-dimensional (3-D) finite-element analysis (FEA) code EMAP3D. Because EMAP3D cannot eject material from the computation in the same manner as the finite-difference code, a "pseudoerosion" algorithm was devised to render cells above the melting temperature nonconducting. A comparison of the two approaches shows results that are in good agreement for depth of magnetic diffusion, current density, and temperature rise, as well as for depth and speed of erosion. These results are encouraging because they suggest that EMAP3D could be used to model melt-wave erosion in realistic 3-D armatures.