熔铸体系炸药装药在加压成型条件下高效提高装药质量的机理研究

The charge quality is the basic guarantee of the safety performance for explosive charges Increasing the pressure of the casting vessel can significantly increase the solidification and cooling rate and improve the charge quality of melt-cast explosives, but the physical mechanism behind the phenomenon remains to be further revealed. By one-dimensional heat conduction test combined with numerical inversion method, the interfacial heat transfer coefficient between the charge and the mold is quantitatively characterized, and the relationship between the cooling rate and the interfacial heat transfer coefficient is properly modeled. Based on the solidification feeding model and on the two competitive mechanisms between the cooling rate and the feeding velocity, the shrinkage and porosity criterion in the melt-cast explosive charge is developed by combining the thermal factors (cooling rate, temperature gradient, etc.) with mechanical factor (pressure of the casting vessel), and the physical meaning of the criterion is demonstrated by a scale-up feeding model. It is expected to reveal the mechanism of the increase of solidification and cooling rate and the improvement of charge quality by increasing the pressure of the casting vessel for melt-cast explosives, to develop the computational and analytical methods for solving the solidification and cooling problems of different melt-cast explosives (different carrier explosives, functional additives and solid content, etc.), and to provide a strong guide for the improvement of charge safety of melt-cast explosives by increasing the pressure of the casting vessel.

装药质量的提高是装药安全性能的根本保证。加压成型工艺可以明显提高熔铸体系炸药装药的凝固冷却速率及装药质量，但该现象背后的物理机制尚有待于进一步揭示。将从装药与模具间的界面换热系数的角度，通过一维导热实验结合数值反演方法定量表征界面换热系数随界面温度及成型圧力的变化规律，建立装药凝固冷却速率与界面换热系数之间的关系模型。基于装药内凝固收缩部位的流动补缩模型，综合考虑补缩通道保持通畅时间（冷却速率）与成型圧力（补缩速度）对补缩效果的竞争机制，建立熔铸体系炸药装药在热学因素（冷却速率、温度梯度等）和力学因素（成型圧力）共同作用下的缩孔缩松判据，通过流动补缩的放大模型阐明缩孔缩松判据的物理内涵。预期可以揭示加压成型工艺提高熔铸体系炸药装药凝固冷却速率及装药质量的机理，建立不同熔铸体系炸药装药在加压凝固冷却过程中的计算及分析方法，为加压成型工艺技术的改进并提高熔铸体系炸药装药的安全性能提供有力指导。

针对加压成型工艺提高装药质量及装药凝固冷却速率的物理现象，本项目通过研究揭示了该现象背后的物理机制。结合一维导热实验及数值反演方法，建立了熔铸装药/模具界面换热系数反演模型。计算结果表明，加压成型工艺提高了装药/模具界面换热系数，这是加压成型工艺提高装药凝固冷却速率的根本原因。通过简化分析不可压粘性流动模型，推导出了补缩通道内的补缩速度与压力梯度之间的解析表达式，进一步导出了补缩通道的凝固收缩临界速度与压力梯度之间的定量关系，建立了加压成型工艺条件下装药内部缩孔缩松形成的判据。本项目研究结果为加压成型工艺的工程化应用奠定了坚实基础。