温度相关的非均质炸药冲击起爆和爆轰宏观反应流模型研究

Study on macroscopic numerical simulations for the shock initiation and detonation propagation of heterogeneous explosives is an important topic in detonation academic research field. In these simulations, a reaction hydrodynamics model consisting of a reaction rate model, an equation of state for unreacted explosives, an equation of state for detonation products and a mixing rule is used to describe the reaction zone of explosives. The pressure-dependent reaction hydrodynamics model or the entropy-dependent reaction hydrodynamics model has many limitations in the numerical simulation. Therefore, the temperature-dependent reaction hydrodynamics model (whose reaction rate model depends on temperature) becomes a development trend of macroscopic reaction hydrodynamics model for shock initiation and detonation. This project would focus on the temperature-dependent WSD(T) and AWSD reaction hydrodynamics models proposed in the past two years. Firstly, theoretical analysis and numerical simulations would be carried out to verify the rationality of the reaction rate model functions used in the two reaction hydrodynamics models. Then, based on the hot-spot information provided by the mesoscale numerical simulation, the two reaction hydrodynamics models would be improved from two aspects: the mixing rule, which is used to construct the equation of state of the mixture in the reaction zone, adopted by the reaction hydrodynamics models is modified from the temperature-pressure equilibrium mixing rule to the ISE mixing rule; and the reaction rate model would be improved to a function depending on the temperature of reaction products. The purpose of this project is to provide a full basis for the rational selection of the reaction rate model function form, thermodynamic variables on which the reaction rate model function depends and the mixing rule for the establishment of a new temperature-dependent reaction hydrodynamics model in the future.

非均质炸药冲击起爆和爆轰波传播过程的宏观数值模拟研究是爆轰领域重要课题。这类模拟需用一个由反应率模型、未反应炸药状态方程、爆轰产物状态方程和混合法则构成的反应流模型描述炸药反应区。基于压力的或基于熵的反应流模型在数值模拟中存在各种局限性，温度相关的反应流模型（其反应率模型依赖于温度）成为宏观反应流模型的一种发展趋势。本项目围绕近两年提出的温度相关的WSD(T)和AWSD反应流模型开展研究工作，首先对它们采用的反应率模型函数形式合理性进行理论分析和数值模拟验证；然后基于中尺度数值模拟提供的热点信息从两个方面对它们进行改进：将反应流模型中用于构建反应区混合物质状态方程的混合法则由温压平衡混合法则修改为ISE混合法则，并将反应率模型改进为产物温度相关的函数。本项目旨在为未来建立新型温度相关反应流模型时反应率模型函数形式、反应率模型函数依赖的热力学量、混合法则的合理选择提供充分的依据。

本项目重点围绕基于反应率是冲击波温度和局部压力函数的AWSD反应流模型开展数值模拟研究工作。通过对TATB基炸药二次冲击加载实验、拐角实验和宽温域下冲击起爆实验开展数值模拟研究，从炸药冲击减敏及初始温度效应方面对AWSD反应模型采用的函数形式合理性进行了评估。为了提高了AWSD反应流模型模拟不同初始温度下炸药起爆和爆轰过程的能力，在AWSD反应流模型中引入了一个孔隙率模型以及初始温度相关的炸药定容比热得到一个新的反应流模型（简称AWSD-R 反应流模型）。通过对宽温域下TATB基炸药的冲击起爆实验、Rate stick实验和双圆柱实验开展数值模拟研究，验证了针对炸药初始温度效应的AWSD模型改进的合理性。将AWSD反应流模型采用的温压平衡混合法则替换为ISE混合法则，然后对TATB基炸药的冲击起爆过程开展了数值模拟，通过在两种混合条件下炸药粒子速度历史、反应度历史、以及炸药化学反应区内热力学物理量的计算结果的比较，分析了将温压平衡混合法则替换为ISE混合法则对基于AWSD反应流模型数值模拟结果的影响。最后，将AWSD反应流模型的反应率压力项函数分别用一个产物温度线性函数和产物温度的指数函数进行替换，得到两个新的反应流模型，通过分别采用这两个新模型开展TATB基炸药在不同强度入射冲击压力下的冲击起爆过程数值模拟研究，对两个新模型的合理性进行了评估。