低温破碎及装药结构对内弹道性能影响的数值分析

Numerical Analysis of Effects of Low Temperature Crushing and Charge Structure on Interior Ballistic Properties Crushing

以大口径火炮密实装药发射安全性为背景,对火药颗粒低温破碎及装药结构对内弹道特性的影响进行了数学建模和仿真分析。针对中心点传火管结构的大口径火炮密实装药,建立传火管及装药床的双一维两相流数学模型,结合膛内火药颗粒应力及破碎度函数,采用数值差分方法对内弹道过程进行数值仿真,研究火药温度及混合装药方案对火药颗粒破碎度及火炮内弹道性能的影响。结果表明,在低温条件下,单一装药结构火药颗粒将发生破碎,且破碎度随温度降低而增大,在-20℃和-40℃条件下,最大破碎度分别达到1.896和2.487,膛内压力分别为690.32MPa和803.64MPa,增幅达到16.4%;在总装药质量6.25kg不变的条件下,小颗粒药装药质量从0增至0.4kg,最大破碎度从2.487减至1.803,膛内压力从803.64MPa减至740.81MPa,由此可见混合装药结构可以有效避免火药颗粒的破碎。

Based on the background of launch safety of large-caliber artillery using high-density loaded propellant charge,the effects of crushing of propellant grains and charge structure on interior ballistic characteristics at low-temperature are modeled and simulated.On account of the high-density loaded propellant charge in a large caliber artillery with a central ignition tube,the two-dimensional two-phase flow mathematical model of the ignition tube and the propellant charge was established.Combined with the function of stress in propellant grains and fragmentation in the barrel,the numerical difference method was used to simulate the internal ballistic circle,and the effects of the temperature and mixed charge on the crushing of propellant grains and internal ballistic performance of the artillery were studied.The results show that propellant grains in single charge structure will crush,and the degree of crushing increases with the decrease of temperature at low temperature.At-20℃ and-40℃,the maximum degree of crushing reaches 1.896 and 2.487,and the chamber pressure is 690.32MPa and 803.64MPa respectively,with an increase of 16.4%.When the mass of propellant charge is constant to 6.25kg,the mass of smaller grains increases from 0kg to 0.4kg in mixed charge,the maximum crushing degree decreases from 2.487 to 1.803,and the pressure in the chamber decreases from 803.64MPa to 740.81MPa.It can be seen that the mixed charge can effectively avoid the breakage of powder particles.