激波与爆轰波对撞的数值模拟研究

NUMERICAL INVESTIGATION ON THE COLLISION BETWEEN DETONATIONS AND SHOCKS

采用二阶精度NND差分格式和改进的二阶段化学反应模型模拟了爆轰波与激波的对撞过程,研究了不同强度入射激波对爆轰过渡区域的影响.当对撞激波较弱时,透射爆轰波演变主要受流动膨胀作用的影响,可划分为对撞影响区、爆轰恢复区和稳定发展区3个阶段,在爆轰恢复区和稳定发展区,前导激波压力经历一个过冲、然后向稳定爆轰过渡的过程,表现了爆轰波熄爆和再起爆的物理特征,当对撞激波较强时,可燃混合气体的高热力学参数导致了更高的化学反应活化程度,形成了弱爆轰向稳定爆轰的直接转变.

Collisions between detonations and shock waves of different strength have been numerically simulated by using NND scheme implemented with the improved two-step chemical reaction model. The collision effects on the detonation transition zone were investigated. In the case of detonation interacting with weaker shock waves, the detonation transition is dominated by flow expansion which lowers the post-shock thermo-states and reduces the chemical reaction rate. The detonation transition can be divided into three stages, named as the collision effect zone, the detonation growth zone and the steady detonation development zone respectively, which indicates some characteristics of detonation-decoupling and reigniting. When detonation interacts with a stronger shock waves, the thermal properties of the explosive mixture are so high that the induced chemical reactions become more active and the flow expansion is compensated. The transition appears to be a direct transformation from a weak detonation to a quasi-steady CJ detonation.