Abstract In this work, based on the ReaxFF-lg reactive force field, the effects of temperature and wax binder on RDX thermal conductivity were studied by using molecular dynamics simulation (MD). The non-equilibrium molecular dynamics (NEMD) method was used to calculate the heat transfer process of RDX crystals with different sizes and at different temperatures and for RDX/wax mixtures with different ratios. The contribution of acoustic and optical phonons to the thermal conductivity was calculated using a thermal conductivity decomposition procedure. The heat transfer process of the RDX supercell and the RDX/wax mixtures were analyzed via calculation of the vibrational density of states. The thermal conductivity of the RDX increased with increasing temperature while the temperature was below 298 K, and decreased slightly with increasing temperature while the temperature was above 323 K. The interfacial thermal resistance between RDX and wax was the main factor that led to a decrease in the thermal conductivity of the RDX/wax mixed explosives. Acoustic phonons played a major role for heat transfer in RDX and mixed RDX explosives. An increased temperature resulted in more frequent expansion or torsion of the bonds in the optical modes, resulting in a slight reduction in the thermal conductivity.

中文翻译：

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温度和蜡粘合剂对 RDX 热导率的影响：分子动力学研究

摘要 本工作基于ReaxFF-lg反应力场，利用分子动力学模拟(MD)研究了温度和蜡粘合剂对RDX热导率的影响。采用非平衡分子动力学(NEMD)方法计算了不同尺寸、不同温度的RDX晶体以及不同比例的RDX/蜡混合物的传热过程。使用热导率分解程序计算声学和光学声子对热导率的贡献。通过计算振动态密度来分析RDX超胞和RDX/蜡混合物的传热过程。当温度低于 298 K 时，RDX 的热导率随温度升高而增加，323 K以上随温度升高而略有下降。RDX与蜡的界面热阻是导致RDX/蜡混合炸药导热系数下降的主要因素。声学声子在 RDX 和混合 RDX 炸药的热传递中起主要作用。升高的温度导致光学模式中键的更频繁的膨胀或扭曲，导致热导率略微降低。