不同点火方式下HMX基PBX炸药反应演化过程的特征分析

Characteristic analysis of reaction evolution process of HMX-based PBX explosive under different ignition modes

在长管强约束条件下对HMX基PBX炸药点火实验进行了数值模拟,分析了点火方式对炸药反应演化规律的影响,获得了弱冲击点火条件下炸药反应演化过程的特征图像。针对黑火药和雷管2种点火方式,分别构建了PBX炸药黑火药点燃和冲击起爆2类实验的唯象模型和数值模拟方法,通过数值模拟获得了钢管内炸药柱反应演化进程的特征图像,柱壳膨胀历程与实验结果符合较好。研究表明,不同点火方式下炸药反应演化进程存在较大差异。如果使用雷管点火,PBX炸药会在几微秒内发生爆轰反应;而使用黑火药点火,PBX炸药会在数毫秒内从缓慢燃烧转化为剧烈爆炸,但随着壳体破裂解体,管内压力骤降,抑制了反应演化向爆轰转变。黑火药点燃条件下整个反应演化过程可以分为4个主要阶段,其中管壁附近炸药柱表面燃烧传播优先于炸药柱中心基体反应,是弱冲击点火反应演化过程的重要特征之一。

Based on the ignition experiment of HMX-based PBX explosive with long tube and strong constraint condition,numerical simulation is carried out by adopting the evolution growth model of explosive explosion reaction and multi-material arbitrary Lagrangian-Eulerian algorithm.The influence of ignition mode on the evolution law of explosive reaction is analyzed,and the characteristic image of explosive reaction evolution process under weak impact ignition condition is also obtained.Phenomenological model and numerical simulation method of PBX explosive ignition experiment under strong constraint conditions are constructed for two ignition modes of black powder and detonator,respectively.The characteristic images of explosive column reaction evolution process in steel pipe are obtained by numerical simulation,and the expansion process of cylinder shell is in good agreement with the experimental result.The study shows that there are great differences in the evolution process of explosive reaction under different ignition modes.If the detonator is used for ignition,the detonation reaction of PBX explosive will occur in a few microseconds;when the black powder is used for ignition while the long tube is strongly constrained,the PBX explosive will change from slow combustion to violent explosion in a few milliseconds.With the cracking and disintegration of the shell,the pressure in the tube will drop sharply,inhibiting the transition to detonation behavior,so the whole reaction evolution process under this ignition mode can be divided into four stages.The combustion propagation on the surface of explosive column near the tube wall takes precedence over the matrix reaction in the center of explosive column,which is an important feature of the evolution process of non-impact ignition reaction.The characteristic image and physical quantity curve obtained in this study reflect the evolution law of explosive reaction under the condition of weak impact ignition,which has important value for deepening the understanding of the hazard risk of explosive charge after accidental ignition.