电作用量在磁驱动固体套筒内爆设计分析中的应用

Application of electrical action to design and analysis of magnetically driven solid liner implosion

磁驱动固体套筒内爆作为标准柱面冲击/准等熵汇聚压缩加载方式,在流体动力学、材料物性和聚变能源等领域具有广泛应用前景.在特定加载条件下,套筒飞层材料、半径和厚度的选择决定了套筒内爆力学行为,而电流烧蚀限制了所能选择的参数范围.通过薄壁套筒假定引入作为动力学参量的电作用量概念,利用不可压缩零维模型给出了低线电流密度下薄壁套筒尺寸优化设计方法和套筒飞层材料选择的原则;将修正后的电阻率-电作用量模型嵌入自编的一维弹塑性磁流体力学程序SOL1D进行模拟计算,分别与FP-1装置及ZR装置上的实验结果进行比对,表明在大径厚比和低线电流密度加载下,利用电作用量估算内爆速度及利用电爆炸丝实验获取的各阶段电作用量判断套筒物理状态是有效的.

As a typical cylindrical-convergent drive technique, magnetically driven solid liner implosion could compress interior substance with a shock or quasi-isentropic manner, which has been widely used to investigate the hydrodynamic behavior, the dynamic characteristics of material and fusion energy and so on. For aspecific facility, the implosion parameters depend on material, radius and thickness of the liner, and the ablation of liner restrict the optional parameters. The concept of electrical action is introduced via thin shell model, which not only is the representation of states for conductive metal, but also indicates the change of liner velocity under the condition of thin shell hypothesis. The result shows that the outer velocity of liner increases linearly with electrical action and is directly proportional to liner thickness but inversely proportional to liner density. The incompressible zero-dimensional model is used to calculate the dynamic parameters of thin shell liner, including the implosion time, the outer interface velocity, the implosion kinetic energy, and the electrical action under the condition of low linear current density. There exist optimal radius and thickness which can achieve the maximum velocity, momentum, and kinetic energy. The aluminum is suitable for reaching higher velocity and the copper can obtain higher pressure according to a proportionality coefficient Qb/ρ which is an intrinsic quality of metal. A one-dimensional(1D) elastic plastic magnetic hydrodynamic code which is called SOL1 D is developed to simulate liner implosion behavior. The modified relationship between resistivity and electrical action is introduced to SOL1D, which can adapt higher hydrodynamic pressure. According to current waves,the 1D code can be used to simulate liner implosion behavior for all kinds of current densities. The 1D simulation liner velocity is in agreement with both the experimental results and the electrical action model for liner implosion experiment on FP-1 facility. The simulation of isentropic compression experiment at ZR facility shows that the magnetic diffusion process is suppressed at extra high current density and hydrodynamic pressure, and the electrical action is larger than the experimental value of wire electrical explosion. The zerodimensional(0 D) and 1D simulation show that estimating the liner velocity and liner phase changing via the electrical action are suitable when thin shell hypothesis and low current density assumption are satisfied.