温压炸药爆炸冲击波在爆炸堡内的传播规律

为研究温压炸药爆炸冲击波在有限空间的传播特征,在爆炸堡中进行400 g RDX/Al/AP(高氯酸铵)/HTPB(端羟基聚丁二烯)温压炸药的爆炸实验,通过压力测试系统得到冲击波在地面和空中的超压时程曲线,以JWL-Miller方程作为爆炸产物状态方程,采用AUTODYN软件对爆炸过程进行了数值模拟,并用数值模拟结果研究冲击波在爆炸堡内发生正反射和斜反射。结果表明,数值模拟得到的冲击波形态、峰值及作用时间与实验测试结果吻合较好,Miller余项能够较为合理地描述含铝温压炸药的后燃特征。正反射发生在装药的地面投影点,反射波峰值达到入射波峰值的3.3倍;斜反射包括规则反射和马赫反射,冲击波入射角小于40°时,在地面形成规则反射,反射波峰值约为入射波峰值的2.5倍;冲击波入射角大于40°时形成马赫反射,马赫波峰值约为入射波峰值的1.2~1.6倍;在侧壁及穹顶发生规则反射。在几何对称轴上发生聚焦现象,聚焦点冲击波超压高于2200 k Pa,达到该点入射冲击波超压的4.3倍,增强了爆炸堡内冲击波,提高了温压炸药的毁伤能力。

Shockwave Propagation Characteristics of Thermobaric Explosive in an Explosion Chamber

In order to investigate the propagation characteristics of shock wave generated by thermobaric explosive,series experiments with thermobaric explosive of RDX/Al/AP/HTPB and the column mass of 400 g were carried out in an explosion chamber. Pressure histories were obtained by piezoelectric measurement system for the measurement points on the ground and in the air. The explosion process was simulated with AUTODYN software using JWL-Miller equation for detonation products. The parameters of JWL-Miller EOS were calibrated by experimental data. Results show that the error of peak pressure and action time between experiment and simulation are too small to be neglected. The Miller remainder can describe the after-burning features of thermobaric explosive reasonably. The simulated pressure distributions show that both normal reflection and oblique reflection occurred in the explosion chamber. Regular reflection and Mach reflection are two forms of oblique reflection. Normal reflection occurs at the ground projective point of the explosive charge. The peak pressure of reflected wave is 3.3 times higher than that of incident wave. Regular reflection occurs at where the incident angle is less than 40°,and the peak of reflected wave is about 2.5 times higher than that of incident wave. Mach reflection occurred at where the incident angle is more than 40°,and the peak of Mach wave is about 1.2-1.6 times higher than that of incident wave. There are regular reflections at side wall and dome. There is focus phenomenon at geometric symmetry axis. The peak overpressure of shock wave on the focus point is above 2200 kPa,and more than 4.3 times higher than that of incident wave. Reflection and focus of shock wave strengthen the overpressure in chamber.