凝聚态炸药中非理想爆轰传播机理的理论与实验研究

As one of the most fundamental problems in detonation physics, the propagation of non-ideal detonation in condensed explosives has a significant engineering background in weapon design. The scaling between detonations propagating with losses in different geometries is directly related to the propagation mechanism of detonation. According to the classic front curvature theory, the scaling of detonation waves between two-dimensional rectangular (slab) geometry and axisymmetric cylinder (tube) geometry is approximately 2:1, but some unanticipated results have showed a scaling of 3-4:1, which indicated that the lateral expansion loss is not the sole mechanism to dominant the detonation propagation. The cause of such a wide variation of observed behaviors is uncertain. The large-scale heterogeneity and hydrodynamic Instability are two possible reasons. Hence, the current project intends to carry out a series of experiments of non-ideal detonation propagation in nitromethane (NM), a type of liquid explosives, and conduct numerical simulations of non-ideal detonation propagation both in homogeneous and heterogeneous explosives to systemically investigate the effects of heterogeneity and instability, as well as confinement on the velocity deficit, the critical dimension of explosives and the structure of detonation. The scaling of near-limit detonation propagating in two-dimensional rectangular geometry and axisymmetric cylinder geometry will be also studied. The aim of this project is eventually reveal the propagation mechanism of non-ideal detonation in condensed explosives, and develop and improve the related models of detonation propagation. Conclusions should be able to provide the basic theoretical support and technical reserves to weapon design.

作为爆轰物理最基础的问题之一，凝聚相非理想爆轰传播问题在武器设计中具有重要的工程应用背景。爆轰波在不同构型中传播的尺寸比例关系与爆轰传播机理直接相关。根据经典的爆轰波阵面曲率理论，爆轰波在柱状炸药和板状炸药中传播的尺寸比例关系约为2：1，但部分实验却获得3-4：1的尺寸比例关系，这说明侧向膨胀损失并不是控制爆轰传播唯一机制。尺寸比例关系大范围波动的起因目前尚无定论，炸药空间非均匀性和流体不稳定性是两个可能的原因。因此，本项目拟开展液体炸药硝基甲烷的非理想爆轰传播的实验研究，开展均匀炸药和非均匀炸药的非理想爆轰传播的数值模拟，系统研究非均匀性、不稳定性以及约束条件对爆速亏损、临界尺寸、爆轰波结构的影响，研究临界极限区域爆轰波在不同构型中传播的尺寸比例关系，以期揭示凝聚相炸药非理想爆轰传播机理、发展和完善爆轰传播相关模型。研究结论可为武器设计提供最基本的理论支持和技术储备。

作为爆轰物理最基础的问题之一，凝聚相非理想爆轰传播问题在武器设计中具有重要的工程应用背景。爆轰波在不同构型中传播的尺寸比例关系与爆轰传播机理直接相关。根据经典的爆轰波阵面曲率理论，爆轰波在柱状炸药和板状炸药中传播的尺寸比例关系约为2：1，但部分实验却获得3-4：1的尺寸比例关系，这说明侧向膨胀损失并不是控制爆轰传播唯一机制。尺寸比例关系大范围波动的起因目前尚无定论，炸药空间非均匀性和流体不稳定性是两个可能的原因。因此，本项目开展了熄爆临近极限区域均匀炸药和非均匀炸药的非理想爆轰传播机理的研究，系统研究了不同约束条件下爆轰波在板状炸药和柱状炸药构型中传播的尺寸比例关系，验证现有爆轰传播模型的适用范围，揭示非均匀性、不稳定性对爆速亏损、临界尺寸、爆轰波结构的影响。研究表明：.1）在不同约束条件下，爆轰波在柱状和板状的均匀炸药中传播均遵从2：1的尺寸比例关系，与经典的爆轰波阵面曲率理论相吻合；验证了爆速与波阵面曲率遵从唯一的函数对应关系；Newtonian理论模型和发展的Eyring波阵面曲率爆速亏损模型能够分别在强约束情况下和弱约束条件下很好的预测爆速-临界尺寸关系。.2）炸药空间的非均匀性导致爆轰波呈现类似于复杂激波相互作用的胞格结构；由随机分布带来的不均匀性更高，爆轰波阵面皱褶得更为厉害。不均匀性的引入可以拓宽爆轰波传播的装药尺寸范围，爆轰波能够在厚度更小的非均匀炸药中传播，随机分布条件下获得的熄灭临界尺寸最小。存在一个最优的非均匀度。.3）不稳定性对于非规则爆轰波的起爆和传播过程具有重要影响。在爆轰波衍射过程中，非规则爆轰波化学反应对前导激波的衰减过程更为敏感，前导激波衰减速率要比规则爆轰波快。从预爆管衍射出的规则爆轰波和非规则爆轰波均可经过壁面反射之后成功二次起爆，不稳定性是控制非规则爆轰波二次起爆的主要机制，而规则爆轰波的二次起爆过程则较为缓和。..