约束HMX基PBX炸药裂缝中燃烧演化实验

Experimental Study on Burning Evolution in Confined HMX-bsaed PBX Cracks

为了研究约束装药裂缝中的燃烧演化规律,获取典型尺寸裂缝中的对流燃烧特性,加深对意外事故条件下武器装药发生点火后转变为高烈度反应过程的机理性认识,采用热点火方式结合高速摄影、压力测量等测试技术,对约束条件下某奥克托今(HMX)基高聚物粘结炸药(PBX)(HMX质量分数为95%)不同宽度预置裂缝(50,100,200μm)中燃烧演化过程开展了实验研究。结果表明,约束装药内部50μm宽裂缝中的对流燃烧能够产生超过250 MPa的压力,燃烧波阵面传播速度超过400 m·s^-1;裂缝越宽,对流燃烧产生的峰值压力越低,燃烧波阵面传播速度越快;炸药裂缝中的对流燃烧演化主要包含4个阶段:较低压力梯度下点火药燃烧产物的早期对流传播(炸药表面未反应);产物气体的稳定对流传播伴随炸药表面燃烧导致的裂缝增压过程;炸药大量燃烧导致急速增压伴随约束壳体变形和炸药破裂;极端高压下约束壳体的解体泄压过程。

The aim of the paper is to investigate the evolution law of burning in high explosive(HE)cracks under confinement,obtain the characteristics of convective burning in typical explosive cracks,and deepen our mechanism understanding on the process for high intensity reaction of projectile fillings under accidental ignition.The propagation of burning in preformed cracks inside octogen(HMX)-based polymer bonded explosive(PBX)(with a content of 95%for HMX)under thermal initiation was re-corded by high-speed camera and pressure transducers.It is found that convective burning in 50μm wide crack of HE under con-finement can produce high pressure exceeding 250 MPa with the burning wave speed exceeding 400 m·s^-1.Comparison between crack widths reveals that with the increase of crack width,the peak pressure attributed to convective burning decreases but the burning wave speed increases.Detailed analysis of experimental data reveals that there are four stages in the evolution of convec-tive burning in explosive cracks.The first stage is the early stage transportation of initial reaction products through crack under rel-atively low pressure gradient without burning on HE surface.The second stage is the steady convection of product gases with pres-sure growing due to combustion inside crack.The third stage is the rapid pressurization due to violent burning of HE with fracture of HE and deformation of the confinement shell.The fourth stage is the confinement failure process under extremely high pressure.