基于Fluent二次开发的电磁轨道发射运动磁场仿真

Simulation on Moving Magnetic Field of Electromagnetic Rail launch Based on Fluent Secondary Development

针对电磁轨道发射运动电磁场与传统运动电磁场存在的差异性,系统推导其运动电磁场的控制方程、边界条件,建立电磁轨道发射运动电磁场的数值计算模型,创新性地提出采用Fluent UDS二次开发进行数值计算的方法,仿真得到速度趋肤效应对电磁轨道发射弹丸内部磁场的影响。仿真结果表明:相比不考虑速度趋肤效应的情况下,在速度趋肤效应的影响下,弹丸中轴线最大磁感应强度由5.6T降到5.2T,且磁感应强度的峰值时刻由放电电流平流段结束时刻提前到平流段的起始时刻。研究方法可对电磁轨道发射膛内多物理场耦合模型的建立提供基础,研究结论可为电磁发射弹丸发射磁场模拟平台的搭建提供设计输入。

Aiming at the difference of moving electromagnetic(EM) field between the EM rail launch and the traditional, this paper deduced the control equations and boundary conditions of EM rail launch moving EM field systematically, and established its numerical calculation model. The method that use fluent user defined scalar(UDS) secondary development to calculate the model was put forward innovatively. The impact of velocity skin effect(VSE) on internal magnetic field of EM rail launch projectile was simulated. Simulation results show that contrast to the case without consideration of VSE the maximum magnetic flux density(MFD) in the central line of projectile decreases from 5.6 T to 5.2 T, and the peak moment of MFD was brought forward from end moment to start moment of the advection section of discharge current. The method in this paper can provide basis for the modeling of in-bore multi-physical coupling of EM rail launch, and the research results can provide design input to the construction of simulation platform of launching magnetic field of EM launch projectile.