凝聚相炸药拐角爆轰的数值模拟

Numerical Simulations of the Corner Detonation of Condensed Phase Explosives

基于多介质可压缩流体方程和炸药反应速率方程构建了三维凝聚相炸药爆轰的物理模型,建立了适用于多相爆轰混合反应区计算的热力学平衡迭代方法并开发了高效稳定的爆轰并行模拟软件,基于对比试验验证了物理模型、数值方法和软件模块的正确性。通过数值模拟不同拐角的爆轰过程,重点研究了凝聚相炸药拐角爆轰的波阵面结构、流场与化学反应的相互耦合和拐角处的二次起爆机理。结果表明,PBX9404炸药135°拐角比90°拐角衍射范围更大,波阵面结构受到当地流场波速的影响;爆轰波绕过拐角后由于流场涡流作用导致化学反应与前导激波解耦,形成临时"死区",随着拐角增大,拐角死区范围扩大;死区二次起爆的关键是混合反应区回爆波的作用时间大于拐角区域起爆的临界诱导时间。

The hybrid detonation formulation of three-dimensional condensed phase explosives is presented based on the multiphase compressible fluid equation and the reaction rate equation. The iteration method of thermodynamic equilibrium for the multiphase detonation mixed reaction zone is built and an efficient detonation parallel software is developed. The feasibility of the physical model, the numerical method and the program module are verified by comparative experiments. We focus on the wave front structure, the coupling of flow fields and chemical reactions and the secondary initiation mechanism of condensed phase explosives by numerical simulations of the detonation process at various corners. The numerical results show that the diffraction area of a corner of 135°is larger than that of 90°of PBX9404 explosive, and the wave front structure is affected by the local flow field velocity. The temporary “death zone” is formed because the chemical reactions are decoupled from the leading shock wave when the detonation wave passes the corner. As the corner angle increases, the dead zone of the corner is expanded. The key of secondary initiation in the dead zone is that the acting time of back-detonation wave should be longer than the critical induction time of explosives in the corner zone.