高压下PBX-1炸药的燃速-压力特性

炸药燃速-压力特性是弹药安全性的关键内因,反映了炸药反应烈度增长的倾向性。为了认识PBX-1炸药在未损伤状态下的燃烧特性,发展了密闭空腔燃烧压力-炸药耗量法以及炸药燃烧速率测试方法,并对PBX-1炸药开展了燃烧实验。采用压力传感器测量了密闭燃烧器内部的压力历程,采用快速响应热电偶监测了炸药燃烧阵面时间-位置数据,获得了炸药燃烧速率并拟合出常温下PBX-1炸药热传导燃烧速率与压力的依赖关系r=(2.16±0.55)p^1.08±0.06。结果表明,PBX-1炸药的压力指数大于1,燃烧速率对压力变化比较敏感,在100 MPa压力范围内燃烧速率呈指数关系,当压力超过100 MPa后燃烧变得不稳定,燃烧速率迅速增加,导致燃烧器内压力骤变。分析其主要原因是,高压下PBX-1炸药发生物理破坏,炸药燃烧比表面积增加100多倍,炸药反应烈度有经对流燃烧机制提升的趋势。

Burn rate-pressure characteristic for PBX-1 explosive at high pressures

The burn rate-pressure characteristic of explosive is the intrinsic factor of ammunition safety, which reflects the potential tendency of the development of reaction violence. We conducted the experiment to understand the deflagration behavior of PBX-1 explosive by using the method of burn pressure-burn consumption in a closed bomb. The temporal pressure data and burn front time-of-arrival data were respectively recorded by pressure transducer and microthermocouple, allowing direct calculation of burn rate as a function of pressure. The result shows that the burn rate equation of PBX-1 explosive can be expressed as r = (2.16±0.55) p1.08±0.06 with the pressure exponent n＞1, indicating that the burn rate is sensitive to pressure. Over the pressure range 10?100 MPa the burn rate displays exponent dependence on the pressure. In contrast, PBX-1 exhibits erratic burn behaviors with pressures grater than 100 MPa and burn rate rises sharply. The analysis demonstrates that the physical deconsolidation of PBX-1 explosive at high pressure is the main factor, which physically disrupts the sample and results in burn specific surface area increasing over 100 times. PBX-1 explosive has potential tendency of enhancing the reaction violence by convective burning mechanism.