炸药内爆驱动多层密绕螺线管的压缩稳定性

Compression Stability of Multi-Layer Composite Close-Wound Solenoid Driven by Explosive Implosion

多层密绕螺线管是炸药柱面内爆磁通量压缩多级MC-1装置的核心构件。设计了一套内爆磁通量压缩装置,初步开展了两级内爆压缩多层密绕螺线管实验,得到了较为清晰的高速摄影图像。密绕螺线管在炸药强爆轰驱动下的界面不稳定性发展是能否获取超高磁场和超高磁压力的关键因素。高速摄影实验结果显示,多层密绕螺线管在内爆过程中没有出现垮塌,套筒内界面仍保持对称性,外界面出现强爆轰导致的周期扰动。为此建立了考虑磁压力的二维有限元内爆数值计算模型,系统研究了密绕螺线管在炸药内爆驱动下的稳定性问题。计算结果表明,炸药网络板多点起爆方式对套筒冲击不稳定性的发展影响较大,网络起爆点数量的增加可以有效抑制套筒界面不稳定性的增长。相比于环氧缓冲层,在炸药与螺线管套筒之间添加1~2 mm的间隙可以更有效地衰减爆轰波引入的周期扰动。

The tightly wound solenoid is the core component of a cascade explosive cylindrical implosion magnetic flux compression device.We designed a solenoid cylinder with composite structure,and carried out two-cascade implosion magnetic flux compression experiment.It is known that the growth of interfacial instability of the solenoid cylinder will determine the amplification of the magnetic field and/or magnetic compressive stress.In the implosion compression event,the projection images of the solenoid by high-speed photography revealed that the inner surface kept in a circle without visible collapse,but cyclic disturbances were observed on the outer surface resulting from explosive detonation.A 2 D finite element model was built to study the instability growth of the solenoid under the explosive implosion.The simulation results displayed that the multi-point network detonation of the explosive played an important role on the solenoid instability.The instability growth can be effectively inhibited by both increasing the number of detonation points and introducing a 1–2 mm thick cavity between the explosive cylinder and the solenoid.