甲烷气体的冲击化学反应流研究

Studies of chemical reaction flows for gaseous methane under shock compression

用二级轻气炮加载技术将W89Mo9Ni1Fe1飞片加速到约5.0km/s,撞击封装有接近常态的甲烷气体的LY12铝靶。利用六通道高温计和示波器记录到冲击压缩的甲烷气体的光辐射历史曲线,并获得甲烷气体的冲击波速度与温度。利用一维Euler方程与化学反应方程的全流场耦合,采用甲烷体系的13组元40反应步的化学反应模型,并用3阶WENO数值格式对空间进行离散。为避免刚性过强,化学反应源项用点隐方法处理。由此得到了甲烷的冲击反应流场和波后热力学参数。通过比较,数值结果与实验结果符合较好。最后,解释了甲烷用作电探针保护气体的物理机制。

Aluminum targets filled with gaseous methane near ambient conditions were impacted by tungsten alloy projectiles which were launched approximately to 5.0km/s from a two-stage light gas gun. The radiant intensities of shock-heated methane varying with time were recorded by means of a six-channel pyrometer and oscilloscopes. The velocities of shock wave and shock temperatures for methane are determined. Eulerian equations coupling with chemical reaction equations involving 13 species and 40-step reactions are solved by using third-order WENO numerical scheme for spatial discretization. The point implicit method is used for chemical source terms to avoid rigid. Then, the chemical reaction flow fields and the thermodynamic properties in the downstream of shock wave are obtained. By comparison, the computational results are agreement with the experimental results. Finally, the physical mechanism of methane applied to as effective atmospheric medium for probes is explained.