Numerical investigation on the muzzle flow field of an underwater submerged launched ballistic gun at different water depths
-
摘要: 为了解弹道枪水下全淹没发射时,水深对膛口流场演化特性的影响,建立了二维轴对称非稳态膛口流场模型。采用流体体积函数多相流模型、标准k-ε湍流模型和Schnerr-Sauer空化模型,结合动网格及用户自定义函数技术,对水下全淹没发射膛口流场演变全过程进行了数值模拟。搭建了弹道枪水下可视化射击实验平台,对12.7 mm口径弹道枪在水中全淹没式发射时膛口流场演化过程进行了观测,并验证了数值模型的合理性。在此基础上,对比了不同水深下(h=1~100 m)膛口流场的演化特性。通过对比发现:在不同水深条件下,在膛口流场影响范围内,弹丸膛外行程随时间的变化均满足指数函数规律;水越深,膛口流场典型波系结构形成所需时间越长,且燃气在膛口轴向马赫盘处的温度和压力峰值越低,压力振荡幅度也越小,更快趋于平稳,但在径向上,水越深,压力振荡持续时间越长。Abstract: To investigate the influence of water depth on the evolution characteristics of the muzzle flow field of an underwater submerged launched ballistic gun, a two-dimensional axisymmetric transient muzzle flow field model was established. The fluid volume function multiphase flow model, standard k-ε turbulence model, Schnerr-Sauer cavitation model, combined with dynamic grid and user-defined function technology, are used to numerically simulate the evolution process of underwater muzzle flow field. An underwater visualized shooting experimental platform for a ballistic gun was built. The evolution process of the muzzle flow field when the 12.7 mm ballistic gun was fully submerged in water was observed, and the rationality of the numerical model was verified. Based on this, the evolution characteristics of the muzzle flow field at different water depths (h=1−100 m) are analyzed and compared. Through comparison, it is found that within the range of the muzzle flow field, the projectile displacement meets the exponential function with time under different water depths; the deeper the water, the longer it takes for the typical wave structure of the muzzle flow field to form, and the lower the peak temperature and pressure of the gas at the axial Mach disc, the smaller the pressure oscillation amplitude, the faster it stabilizes. but in the radial direction, the deeper the water depth, the longer the duration of pressure oscillations.
-
Key words:
- ballistic gun /
- submerged launch /
- underwater launching /
- muzzle flow field /
- Mach disk /
- evolutionary characteristics
-
表 1 膛口初始参数
Table 1. Initial parameters for the muzzle
h/m l/m v0/(m·s−1) pk0/MPa 1 1 230 14.5 50 1 220 15.5 100 1 207 20.5 表 2 拟合参数
Table 2. Fitting parameters
h/m x0/m x1/m t1/ms 1 1.09 1.09 4.55 50 0.84 0.84 3.55 100 0.79 0.79 3.42 -
[1] 李鸿志, 姜孝海, 王杨, 等. 中间弹道学[M]. 北京: 北京理工大学出版社, 2015: 10. [2] 姜孝海, 范宝春, 李鸿志. 膛口流场动力学过程数值研究 [J]. 应用数学和力学, 2008, 29(3): 316–324. DOI: 10.3879/j.issn.1000-0887.2008.03.006.JIANG X H, FAN B C, LI H Z. Numerical investigations on the dynamic process of the muzzle flow [J]. Applied Mathematics and Mechanics, 2008, 29(3): 316–324. DOI: 10.3879/j.issn.1000-0887.2008.03.006. [3] 吴伟, 许厚谦, 王亮, 等. 含化学反应膛口流场的无网格数值模拟 [J]. 爆炸与冲击, 2015, 35(5): 625–632. DOI: 10.11883/1001-1455(2015)05-0625-08.WU W, XU H Q, WANG L, et al. Numerical simulation of a muzzle flow field involving chemical reactions based on gridless method [J]. Explosion and Shock Waves, 2015, 35(5): 625–632. DOI: 10.11883/1001-1455(2015)05-0625-08. [4] 陈川琳, 黄陈磊, 许辉, 等. 小口径步枪弹头后效期运动特性试验与数值研究 [J]. 兵工学报, 2019, 40(2): 265–275. DOI: 10.3969/j.issn.1000-1093.2019.02.006.CHEN C L, HUANG C L, XU H, et al. Experimental and numerical research on motion characteristics of a small caliber bullet in muzzle flows [J]. Acta Armamentarii, 2019, 40(2): 265–275. DOI: 10.3969/j.issn.1000-1093.2019.02.006. [5] 张欣尉, 余永刚. 水下发射对机枪膛口温度场影响的数值分析 [J]. 含能材料, 2017, 25(11): 932–938. DOI: 10.11943/j.issn.1006-9941.2017.11.008.ZHANG X W, YU Y G. Numerical analysis for the effect of underwater launch on the temperature field of machine gun muzzle [J]. Chinese Journal of Energetic Materials, 2017, 25(11): 932–938. DOI: 10.11943/j.issn.1006-9941.2017.11.008. [6] 张欣尉, 余永刚, 莽珊珊. 装药参数对水下机枪密封式膛口流场影响的数值分析 [J]. 兵工学报, 2018, 39(1): 18–27. DOI: 10.3969/j.issn.1000-1093.2018.01.002.ZHANG X W, YU Y G, MANG S S. Numerical analysis of influence of charge parameters on flow field around sealed muzzle of underwater machine gun [J]. Acta Armamentarii, 2018, 39(1): 18–27. DOI: 10.3969/j.issn.1000-1093.2018.01.002. [7] HU Z T, YU Y G. Expansion characteristics of multiple wall jets in cylindrical observation chamber [J]. Applied Thermal Engineering, 2017, 113: 1396–1409. DOI: 10.1016/j.applthermaleng.2016.11.140. [8] ZHAO J J, YU Y G. Flow structure of conical distributed multiple gas jets injected into a water chamber [J]. Journal of Mechanical Science and Technology, 2017, 31(4): 1683–1691. DOI: 10.1007/s12206-017-0316-9. [9] ZHOU L L, YU Y G. Study on interaction characteristics between multi gas jets and water during the underwater launching process [J]. Experimental Thermal and Fluid Science, 2017, 83: 200–206. DOI: 10.1016/j.expthermflusci.2017.01.007. [10] 郝宗睿, 王乐勤, 吴大转. 水下喷气推进高速射流场数值研究 [J]. 浙江大学学报(工学版), 2010, 44(2): 408–412. DOI: 10.3785/j.issn.1008-973X.2010.02.036.HAO Z R, WANG L Q, WU D Z. Numerical simulation of high-speed jet flow field of underwater jet propulsion craft [J]. Journal of Zhejiang University (Engineering Science), 2010, 44(2): 408–412. DOI: 10.3785/j.issn.1008-973X.2010.02.036. [11] 唐云龙, 李世鹏, 谢侃, 等. 有相变的水下超音速燃气射流数值模拟 [J]. 哈尔滨工程大学学报, 2016, 37(9): 1237–1243. DOI: 10.11990/jheu.201506010.TANG Y L, LI S P, XIE K, et al. Numerical simulation of underwater supersonic gas jets with phase transitions [J]. Journal of Harbin Engineering University, 2016, 37(9): 1237–1243. DOI: 10.11990/jheu.201506010. [12] 张焕好, 郭则庆, 王瑞琦, 等. 水下超声速气体射流的初始流动特性研究 [J]. 振动与冲击, 2019, 38(6): 88–93, 131. DOI: 10.13465/j.cnki.jvs.2019.06.013.ZHANG H H, GUO Z Q, WANG R Q, et al. Initial flow characteristics of an underwater supersonic gas jet [J]. Journal of Vibration and Shock, 2019, 38(6): 88–93, 131. DOI: 10.13465/j.cnki.jvs.2019.06.013.