Numerical study of current distribution under high-velocity in railgun with moving boundary conditions

• Jinghan Xu ^[1] ; Shengguo Xia ^[1] ; Lixue Chen ^[1] ; Anbang Gu ^[1] ; Hongdan Yang ^[3] ; Chengxian Li ^[2]
  1. [1] Huazhong University of Science and Technology

     Huazhong University of Science and Technology

     China

     
  2. [2] Naval University of Engineering

     Naval University of Engineering

     China

     
  3. [3] Southwest Electric Power Design Institute, Chengdu, China

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• Localización: Compel: International journal for computation and mathematics in electrical and electronic engineering, ISSN 0332-1649, Vol. 44, Nº 1, 2025, págs. 93-108
• Idioma: inglés
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  • Purpose – The purpose of this paper is to investigate the moving boundary conditions on the sliding armature and rail (A/R) interface. As the computational domains involve both moving and stationary conductors, Lagrangian description and backward difference schemes are adopted for spatial and temporal discretization, arising discontinuities in variables. The proposed formulation can compute the current distribution under high velocities (∼km/s) without numerical oscillations and avoids mesh re-generation, saving computational resources.

    Design/methodology/approach – The governing equations in Lagrangian description, backward difference schemes and derivations of moving boundary conditions are shown in detail. The interface matrix is explicitly enforced on the whole domain matrix and pseudocodes are presented for implementation. Moreover, shifted interpolated quantity method is proposed to deal with unevenly sized mesh, which can calculate acceleration scenarios and save computation resources under high velocities. Comparative calculations with previous methods under low velocities are conducted to verify the correctness of computational and physical models.

    Findings – The current distributions with constant velocities are consistent with previous two-dimensional and low-velocity studies, further verifying the correctness of the method. The three-dimensional high-velocity results show that the current tends to concentrate near the trailing edge of A/R interface and diffuses into the bulks over time, with higher velocity contributing to less significant current diffusion. The velocity skin effect precedes the magnetic diffusion, conductivity and other factors that influence the current distribution.

    Originality/value – The proposed methods can compute the current distributions in railgun under velocity accelerated to over 2,000 m/s, and the results provide more comprehensive understandings of the current evolution process under velocity skin effect in railgun.