轴向脉冲电流对射流线性不稳定性的作用

为了提高电磁被动装甲对聚能射流的防护能力,利用叠加原理和磁流体线性不稳定理论,在轴向脉冲电流作用下建立了射流运动线性扰动控制方程,并对射流箍缩和扭曲不稳定性增长率随粘性、时间的变化规律进行了分析,得到了射流不稳定增长率和射流的变形规律,并利用数值方法得到了射流变形的计算公式。最后通过直径39.2mm破甲弹进行静破甲试验,通过后效板射流入射孔的大小验证了脉冲电流对射流的箍缩作用;利用具有初始弯曲、直径为1.75mm铜丝模拟了脉冲电流对射流的扭曲作用,通过铜丝的变形验证了脉冲电流对射流的扭曲作用。实验结果证实了理论分析的正确性。

Linear unstable effect on shaped-charge jet under axial pulse current

To improve the capability of passive electromagnetic armor against shaped charge jet (SCJ), the linear perturbation control equation of SCJ under the axial pulse current is constructed by magneto hydrodynamic instability theory and superposition theorem, and the variation law of SCJ pinching and kinking instability growth rates related to viscosity and time are analyzed. The deformation trend of SCJ is obtained and the formula used to calculate the SCJ deformation can be get by numerical means. Finally, the static penetration experiment with 39.2 mm diameter armor-piercing projectile and the kinking experiment with 1.75 mm diameter copper wire are carried out. The experimental results demonstrate that the axial pulse current can destroy the SCJ because of necking or kinking perturbation and confirm the validity of the theoretical analysis.