基于慢烤实验的混合炸药热传导系数计算方法

Calculation Method of Thermal Conductivity of Explosives Based on Slow Cook⁃off Experiment

热传导系数作为炸药的重要热力学参数,显著影响炸药装药的点火响应特性。在未开展炸药热传导系数测定实验的情况下,为了快速有效确定一种新型炸药热传导系数,针对典型圆柱段装药结构,建立了轴对称热传导理论模型,获得混合炸药热传导方程的稳态解析解,提出了基于慢烤实验数据的混合炸药热传导系数计算方法。确定了新型不敏感炸药GOL-1(HMX/Al/AP/Binder)的热传导系数,典型烤燃条件下小尺寸装药结构点火响应数值模拟计算结果显示:不同加热速率下装药中心温升曲线计算结果与实验结果均吻合较好,点火时刻装药中心位置温度和点火时间的计算结果与实验偏差最大为2.27%和1.12%,表明GOL-1炸药热传导系数的有效性及数值模拟方法的可行性。建立的热传导计算方法揭示了慢烤装药温度-时间曲线中包含的炸药导热特性及规律,相比体积加权方法和串/并联导热模型方法更适用于计算混合炸药热传导系数,在缺少新型炸药热传导系数测定实验数据的情况下,不失为一种有效的确定方法,为弹药热安全性设计与评估提供了炸药基础参数,推动安全弹药数字化设计与量化评估发展。

As an important thermodynamic parameter of explosives,thermal conductivity significantly affects the ignition response characteristics of explosive charge.In order to quickly and effectively obtain the thermal conductivity of explosives without tests,an axisymmetric heat conduction theoretical model of typical cylindrical charge structure is established,and its steady-state analytical solution is derived.Also,a method for calculating the thermal conductivity of explosives is proposed based on the slow cook-off experimental data.The thermal conductivity of a new type of insensitive explosive,GOL-1(HMX/Al/AP/Binder),is determined.The numerical simulation results of the ignition response of small-size charge structure under typical cook-off conditions shows that the calculated results of the charge center temperature-time curves at different heating rates are ba-sically consistent with the experimental results,and the deviations of ignition temperature at charge center and ignition time between the calculated and experimental results are 2.27%and 1.12%at most,which indicates the effectiveness of the thermal conductivity of the GOL-1 and the feasibility of the numerical simulation method.The established calculation method reveals the thermal conductivity characteristics and rules based on the temperature-time curves of slow cook-off experiments,which is more suitable for calculating the thermal conductivity of explosives compared with volume-weighted method and string or parallel heat conduction model.In the absence of experimental data for determining the thermal conductivity of new explosives,this method is an effective determination method,providing a basic parameter for the design and evaluation of thermal safety of ammunition and promoting the development of digital design and quantitative evaluation of safe ammunition.