电磁轨道炮三维瞬态涡流场的有限元建模与仿真

Finite Element Analysis of 3D Transient Eddy Field in Electromagnetic Railgun

本文分析了固体电枢电磁轨道炮的三维瞬态涡流问题,建立了运动坐标下的磁扩散公式,该公式基于准稳态麦克斯韦方程组,用矢量磁位和标量电位作为未知量。在运动坐标下计算含有运动导体的磁扩散问题,可以消除高速情况下的数值不稳定,减少计算量和内存需求。通过施加库仑规范,保证了方程解的唯一性。本文以方膛电磁轨道炮为例,用有限元法和后向差分格式对方程组进行了求解,得到了轨道炮中电流密度的分布,以及电流和电枢速度的变化过程。

The 3D transient eddy of railgun with solid armature was analyzed,the Lagrangian formulations of electromagnetic diffusive processes with moving coordinate based on quasi-static Maxwell＇s equations were established by magnetic vector and electric scalar potentials.Lagrangian description of field variables exhibits several advantages in modeling electromagnetic diffusive problems with moving coordinate,i.e.the numerical instability at hypervelocity can be eliminated,the computational cost and memory requirement can be reduced.With Coulomb gauge condition,magnetic vector potential is uniquely determined.Numerical simulation was carried out on a square bore railgun by the finite element and the backward difference method,to obtain the distribution of current densities and the profiles of current and armature velocity.