长管强约束条件下压装PBX炸药点火实验研究

为探究压装炸药PBX-A在较强约束条件下、在药柱一端使用点火药引燃后能否发生燃烧转爆轰，在传统DDT管的基础上重新设计了特定位置约束增强的厚壁钢柱壳管实验装置，利用多路PDV诊断技术，配套高速摄影记录对点火药引燃炸药实验过程中的柱壳膨胀、断裂特性等实验现象进行了全过程连续监测。对比由爆轰驱动的相同装药条件下实验现象及对应过程物理状态的区别，发现：爆轰实验和点火实验 的总反应时间历程存在数量级的差别；柱壳上各个测点速度历程反映出装置内部炸药反应引起的压力增长历程特征，以及炸药反应的传播过程均存在明显差异。分析表明，在较强约束条件下，典型压装炸药PBX-A在一端使用点火药引燃后的反应行为实际是以高温、高压反应产物沿装药缝隙对流，炸药表面的层流燃烧及其伴随的结构响应行为为主要表现形态；从反应压力水平及其增长的时间历程来看，炸药基体中没有形成冲击波，因而无法实现从冲击到爆轰的转变。

Experimental study on initiated reaction evolution of pressed explosives in long thick wall cylinder confinement

In order to investigate whether the reaction evolution of pressed HMX-based PBXs inside long thick wall steel tube initiated by ignition composition leads to detonation finally or not, a new experiment apparatus was designed based on traditional DDT tube, in which the strength of tube at specific locations is enhanced, and multichannel PDV probes and high speed photography were used to diagnose the expansion process and rupture characteristics of tube wall. Compared with the results initiated by detonator in the same explosives and confinement, the reaction durations of detonation and ignition differed by orders of magnitude; the pressure evolution measured by tube wall velocities, and the propagation process of tube wall movement were significantly different in two reactions. Analysis shows that the convective flow of reaction products along the seam between tube wall and explosives, high temperature and pressure, dominated the reaction evolution of PBX-A initiated by ignition composition under strong confinement, and appeared as laminar burning on explosive surface and structural response of confinement. There is no reaction activated in explosive bulk by the ramp wave caused by upper stream non shock initiation reaction, least of all DDT.