Impact initiation of a solid-rocket engine by a shaped-charge jet
-
摘要: 为研究聚能金属射流对固体火箭发动机的冲击响应,开展了聚能装药空射实验及某尺寸发动机在无防护情况下的射流冲击实验,使用高速摄影仪记录了爆炸响应过程,并测量了不同距离及方向的空气超压和破片速度。利用AUTODYN有限元计算软件对实验过程进行了数值模拟,通过调整流固耦合的网格大小,避免了耦合泄漏。实验结果表明,火箭发动机受到射流冲击后,会发生剧烈爆炸,推进剂完全反应,破片速度达4 700 m/s以上,距离发动机爆炸中心1 m处的空气超压达到19.78 MPa,爆炸中心温度达到3 000 ℃以上,该推进剂爆炸能量略高于常规炸药。模拟结果显示,射流以头部速度7 000 m/s的速度冲击发动机壳体后,射流头部的尖端被严重烧蚀,且速度降至约5 600 m/s;推进剂在受到射流侵彻1~2 mm后,发生剧烈反应;爆炸冲击波以球形沿圆柱孔装药传播,并通过圆柱形中心孔冲击另一侧推进剂,发生装药的二次冲击起爆,同时伴有回爆现象,在推进剂中心的高斯点出现了3次超压波峰;距离发动机中心1 m处3个高斯点的平均空气压力峰值为18.75 MPa,与实验结果吻合较好。Abstract: In order to study the impact of the metal jet formed by a shaped charge on a solid-rocket engine, the shaped-charge blasting experiment was carried out, and the jet impingement experiment was performed for the shaped jet impacting a certain-size engine without protection. A high-speed camera was used to record the response processes of the explosions. Air overpressures and fragment velocities were measured at different distances and in different directions. The jet forming process and the jet-impacting-motor process were numerically simulated by using the finite element software AUTODYN. And in the simulation, the problem of fluid-solid coupling grid leakage was avoided by adjusting the grid thickness. The experimental results show that when the rocket engine was impacted by the jet, it exploded violently and the propellant reacted completely. The steel equipment fixing the rocket engine after the explosion was almost destroyed completely. The velocity of fragments reached above 4 700 m/s. The air overpressure at 1 m away from the explosion center of the engine reached 19.78 MPa. Through the pictures collected by the high-speed camera, it could be judged that the temperature in the explosion center reached above 3 000 ℃. According to the peak of the air overpressure and the law of air similarity, the energy produced by this type of propellant explosion was slightly higher than those produced by explosives such as 8701 and TNT. The simulated results show that when the jet impinged on the engine shell at the head velocity of 7 000 m/s, the tip of the jet head was severely ablated, and the velocity of the jet head decreased to about 5 600 m/s; the propellant reacted violently while being penetrated 1−2 mm by the jet; the shock wave propagated along the propellant in a spherical shape, and the propellant on the other side underwent shock initiation twice with a retonation; there were three overpressure peaks at the Gauss point located in the center of the propellant. The first peak was generated by the shock wave from the left side; the second peak was due to the shock wave hitting the solid wall of the propellant and a certain wave surface reflection was generated, causing a pressure rise; the third peak was caused by a new shock wave generated by the retonation. The simulated average air overpressure peak is 18.75 MPa at the three Gauss points set at 1 m from the center of the engine, which is in good agreement with the experimental results.
-
Key words:
- shock initiation /
- shaped-charge jet /
- solid-rocket motor /
- retonation
-
表 1 爆炸产生的空气超压峰值
Table 1. Air overpressure peaks induced by blasting
传感器 距离/m 聚能装药空射超压压力峰值/MPa 射流冲击发动机超压压力峰值/MPa 1 1 0.654 70 19.780 2 1 0.526 20 3 2 0.043 24 4 2 0.033 49 3.014 表 2 爆炸产生的破片速度
Table 2. Velocities of blasting-induced fragments
测速栅靶 速度/(m·s−1) 1 4790.42 2 4752.48 表 3 药型罩、发动机壳体和端盖材料模型
Table 3. Material models for the shaped-charge line, engine shell and end cover
部件 材料 状态方程 强度模型 侵蚀准则 药型罩 Cu-OFHC Shock Steinberg Guinan Geometric strain 发动机壳体 Kevlar Ortho Elastic Geometric strain 发动机端盖 Al-7039 Shock Johnson Cook Geometric strain 表 4 8701炸药JWL本构方程参数
Table 4. Parameters in JWL equation of state for the explosive 8701
A/GPa B/GPa R1 R2 ω 854.5 20.493 4.60 1.35 0.25 表 5 推进剂Lee-Tarver本构方程参数
Table 5. Parameters in Lee-Tarver equation of state for the propellant
R1 R2 ω A/GPa B/GPa I b a x G1 c d y G2 e g z 5 1.82 0.2 909.59 62.05 44 0.222 0.01 4 111 0.222 0.667 1.66 200 0.333 0.667 2 -
[1] 张浩波. 反坦克弹药作用原理[M]. 北京: 国防工业出版社, 1980: 153. [2] HELD M. Critical area for the initiation of high explosive charges [M] // ASAY J R, GRAHAM R A, STRAUB G K. Shock Waves in Condensed Matter 1983. Amsterdam: North Holland, 1984: 555−557. DOI: 10.1016/B978-0-444-86904-3.50126-3. [3] HELD M. Initiation criteria of high explosives at different projectile or jet densities [J]. Propellants, Explosives, Pyrotechnics, 1996, 21(5): 235–237. DOI: 10.1002/prep.19960210505. [4] HELD M. Initiierung von sprengstoffen, ein vielschichtiges problem der detonationsphysik [J]. Explosivstoffe, 1968, 5: 98. [5] 张超, 党永战, 李宏岩, 等. 固体推进剂对射流刺激的易损性响应 [J]. 火炸药学报, 2014, 37(2): 69–72. DOI: 10.3969/j.issn.1007-7812.2014.02.015.ZHANG C, DANG Y Z, LI H Y, et al. Vulnerability response of solid propellant to shaped charge jet impact [J]. Chinese Journal of Explosives and Propellants, 2014, 37(2): 69–72. DOI: 10.3969/j.issn.1007-7812.2014.02.015. [6] 王建灵, 俞统昌, 郭炜. 一种射流源和炸药射流感度的研究 [J]. 爆炸与冲击, 2007, 27(4): 370–374. DOI: 10.11883/1001-1455(2007)04-0370-05.WANG J L, YU T C, GUO W. Studies on a shaped charge jet and the jet sensitivity of explosives [J]. Explosion and Shock Waves, 2007, 27(4): 370–374. DOI: 10.11883/1001-1455(2007)04-0370-05. [7] 王利侠, 谷鸿平, 丁刚, 等. 聚能射流对带壳浇注PBX装药的撞击响应 [J]. 含能材料, 2015, 23(11): 1067–1072. DOI: 10.11943/j.issn.1006-9941.2015.11.006.WANG L X, GU H P, DING G, et al. Reaction characteristics for shelled cast-cured PBX explosive impacted by shaped charge jet [J]. Chinese Journal of Energetic Materials, 2015, 23(11): 1067–1072. DOI: 10.11943/j.issn.1006-9941.2015.11.006. [8] 张先锋, 丁建宝, 赵晓宁. 夹层聚能装药作用过程的数值模拟 [J]. 爆炸与冲击, 2009, 29(6): 617–624. DOI: 10.11883/1001-1455(2009)06-0617-08.ZHANG X F, DING J B, ZHAO X N. Numerical simulation of double layer shaped charge [J]. Explosion and Shock Waves, 2009, 29(6): 617–624. DOI: 10.11883/1001-1455(2009)06-0617-08. [9] 恽寿榕, 赵衡阳. 爆炸力学[M]. 北京: 国防工业出版社, 2005: 192. [10] 雍占锋. 基于图像处理的火焰监测与燃烧诊断技术[D]. 北京: 北京化工大学, 2007. [11] 伍俊英, 陈朗, 鲁建英, 等. 高能固体推进剂冲击起爆特征研究 [J]. 兵工学报, 2008, 29(11): 1315–1319. DOI: 10.3321/j.issn:1000-1093.2008.11.007.WU J Y, CHEN L, LU J Y, et al. Research on shock initiation of the high energy solid propellants [J]. Acta Armamentarii, 2008, 29(11): 1315–1319. DOI: 10.3321/j.issn:1000-1093.2008.11.007. [12] 崔浩, 郭锐, 宋浦. 固体火箭发动机跌落安全性数值分析 [J]. 兵工学报, 2018, 39(S1): 66–71.CUI H, GUO R, SONG P. Numerical analysis of safety of solid rocket engine during falling process [J]. Acta Armamentarii, 2018, 39(S1): 66–71. [13] 仲倩, 王伯良, 黄菊, 等. TNT空中爆炸超压的相似律 [J]. 火炸药学报, 2010, 33(4): 32–35. DOI: 10.3969/j.issn.1007-7812.2010.04.008.ZHONG Q, WANG B L, HUANG J, et al. Study on the similarity law of TNT explosion overpressure in air [J]. Chinese Journal of Explosives and Propellants, 2010, 33(4): 32–35. DOI: 10.3969/j.issn.1007-7812.2010.04.008. [14] 朱亮, 李慧子, 王晓鸣, 等. 炸药材料性能参数对JPC成型的影响 [J]. 四川兵工学报, 2011, 32(3): 13–16. DOI: 10.3969/j.issn.1006-0707.2011.03.005.ZHU L, LI H Z, WANG X M, et al. Impact of performance parameter in explosive material for JPC molding [J]. Sichuan Ordnance Journal, 2011, 32(3): 13–16. DOI: 10.3969/j.issn.1006-0707.2011.03.005. [15] 王省身, 谢之康. 矿井沼气爆炸安全距离的探讨 [J]. 中国矿业大学学报, 1989, 18(4): 1–8.WANG X S, XIE Z K. A discussion on the safety distance in case of gas explosion [J]. Journal of China University of Mining and Technology, 1989, 18(4): 1–8. [16] 慈明森. 金属在大变形、高应变率和高温条件下的本构模型和数据 [J]. 弹箭技术, 1998(3): 32–44. [17] 章冠人, 陈大年. 凝聚炸药起爆动力学[M]. 北京: 国防工业出版社, 1991: 131−134; 150−153. [18] 邓全农, 胡栋, 丁儆, 等. 回爆现象的研究及其临界曲线 [J]. 爆炸与冲击, 1986, 6(3): 193–197.DENG Q N, HU D, DING J, et al. Studies of retonation phenomena and its critical curve [J]. Explosion and Shock Waves, 1986, 6(3): 193–197.