金属微层裂区气体渗入现象的一种近似理论分析

Approximate theoretical analysis of gas penetration in metal micro spallation

受高压冲击后金属内激波在金属-气体界面卸载,当金属熔化后形成微层裂现象.微层裂发展到一定程度后,高压气体透过接触面向金属熔化液滴间零压真空缝隙渗透.本文就气体渗入金属微层裂区的现象进行了相关理论分析研究.基于金属液滴的正六面体周期性排布,采用准静态和半动态分析方法,近似分析了气体渗入微层裂区的现象,得到了气体渗入通道封闭时间、最大渗入深度、单位面积渗入气体质量等近似公式.由敏感性分析看到,理论分析给出的物理现象变化规律符合该问题中的基本物理认识.

After high pressure shock,the shock wave in the metal is unloaded at the metal-gas interface,and micro spallation occurs when the metal melts.When the micro spallation develops to a certain extent,the high pressure gas penetrates the zero pressure vacuum gap between the metal melt droplets.In this paper,the phenomenon of gas penetrating metal micro spallation zone is analyzed theoretically.Based on the regular hexahedron periodic arrangement of metal droplets,the calculation formulas of the maximum penetration depth,the sealing time of the penetration channel and the maximum mass of the gas penetrating the metal micro spallation zone are given through theoretical analysis under the quasi-static and semi-dynamic conditions.The quasi-static process is considered to be the gas penetration process that can be approximated as the escape process of gas into the vacuum,and the gap in the metal micro spallation zone will be filled with gas.The semidynamic analysis is based on two basic assumptions:one is the equal droplet size and spacing in the micro spallation zone and the other is the critical sealing condition of gas penetration.In the process of semi-dynamic analysis it is demonstrated that the initial critical sealing distance is independent of the shape factor of the droplet single control volume.The semi-dynamic analysis can give various critical sealing information when the gas stops penetrating the metal micro spallation zone.The results of quasi-static analysis can be used as the upper limit of gas penetration,and the semi-dynamic analysis results can be used as the lower limit of gas penetration.From the sensitivity analysis,it can be seen that the change law of physical phenomena given by theoretical analysis accords with the basic physical understanding of the problem.Through this study,the upper and lower limit of the mixed state of gas penetrating the metal micro spallation zone can be estimated,which can provide more accurate initial metal-gas mixed state for subsequent research of the evolution of mixed state.The theoretical analyses given in this paper are based on a lot of uncertain assumptions,and the in-depth study of this phenomenon is still needed based on the law summary and mutual confirmation of experiment and simulation.