低温撞击破碎高能发射药结构特征与高压燃烧性能研究

摘要

DAGR125 and NR11 gun propellants with different fragmentation degree were prepared by impact of dropping hammer at-40℃.The fragmentation degree of the gun propellants was characterized by the absorption quality of dye (AQD);Combined with the closed high pressure bomb experiment, the relationship of the structure feature and combustion feature of fragmented gun propellants at high pressure was analyzed.The results show that the change rate of dynamic vivacity occurs a mutation in the initial combustion stage with increasing the quality of small particles gradually.When the fragmentation degree is low, the initial dynamic vivacity and the AQD can be used to measure the initial combustion surface and the fragmentation degree of the gun propellants;When the fragmentation degree is high enough, the initial dynamic vivacity measured by traditional method is obviously lower than actual value, and it is unsuitable to represent the initial combustion surface, however the AQD method is more accurate.The change rule of initial dynamic vivacity shows that the fragmentation degree of propellant grains increases rapidly when the height of dropping hammer is greater than 60cm.The change in dynamic vivacity reveals that the whole combustion process of DAGR125 and NR11 fragmented gun propellants converts from progressive combustion to reduced combustion when the height of dropping hammer is greater than 23.0cm and 23.1cm, respectively.%在-40℃下,通过落锤撞击制备了不同破碎程度的DAGR125和NR11发射药,利用染料吸附量表征了发射药的破碎程度,结合密闭高压爆发器实验,分析了破碎发射药结构特征与高压燃烧特征的关系.结果表明,随着小颗粒破碎发射药的增加,动态活度变化率在燃烧初始阶段发生转折.当破碎程度较小时,初始动态活度、染料吸附量均可衡量发射药初始燃面和破碎程度;当破碎程度较大时,利用传统方法获取的初始动态活度明显小于实际值,不适合用来表征初始燃面,而染料吸附量法更为准确.初始动态活度变化规律显示,当落锤高度大于60cm时,发射药药粒的破碎程度快速增加;动态活度变化规律显示,落锤高度分别大于23.0cm和23.1cm时,DAGR125和NR11破碎发射药整体燃烧过程由增面性转变为减面性.