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兵工学报 ›› 2024, Vol. 45 ›› Issue (12): 4383-4394.doi: 10.12382/bgxb.2023.1041

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水下火炮气幕式发射膛口流场演化特性的数值分析

柏雯斌, 余永刚*(), 张欣尉   

  1. 南京理工大学 能源与动力工程学院, 江苏 南京 210094

Numerical Analysis of Muzzle Flow Field Characteristics of Underwater Gun Using Gas Curtain Launch

BAI Wenbin, YU Yonggang*(), ZHANG Xinwei   

  1. School of Energy and Power Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu, China
  • Received:2023-10-24 Online:2024-12-30

摘要:

为研究水下火炮采用气幕式发射条件下的膛口流场演化特性,建立气幕式发射二维非稳态膛口两相流模型,并验证模型的正确性,随后对30mm滑膛式火炮气幕式发射的膛口初始射流流场及燃气射流流场进行数值模拟。计算结果表明:在弹丸推动作用下,弹前气幕向膛外扩展形成初始射流;初始射流先在膛口附近形成两道斜入射激波,并在中心轴线处发生正规反射,随着气幕内环境压力的衰减,两道入射激波又在近轴线区域发生非正规反射,形成初始射流瓶状激波结构;初始射流马赫盘位置基本保持不变,直径随时间呈线性增长,弹丸出膛后,火药燃气迅速向弹丸侧前方扩展,并快速吞噬初始射流马赫盘,在t=210μs时,入射激波首先在弹底壁面发生非正规反射,随后在靠近轴线处又发生两次非正规反射,形成双三波点的瓶状激波结构,燃气射流马赫盘轴向位移随时间呈指数衰减规律,直径呈现增长-突增-稳定的趋势。

关键词: 水下发射, 膛口流场, 激波反射, 瓶状激波, 马赫盘

Abstract:

A two-dimensional unsteady numerical model for the muzzle two-phase flow field is established to study the muzzle flow field characteristics of underwater gun using gas curtain launch. The accuracy of the numerical model is verified, and the initial jet flow field and gunpowder gas jet flow field at the muzzle of 30mm smoothbore gun using gas curtain launch are simulated. The numerically simulated results indicate that the gas curtain in front of the projectile expands out of the muzzle to form an initial jet under the propulsion of projectile, and two oblique incident shock waves generated by initial jet near the muzzle normally reflect at the central axis. As the ambient pressure within the gas curtain decays, two incident shock waves undergo Mach reflection at the central axis, resulting in the formation of a bottle-shaped shock wave structure then. The displacement of Mach disk of initial jet remains relatively constant, but it’s diameter linearly increases over time. Once the tail of projectile exits the muzzle, the gunpowder gas rapidly expands towards the front of projectile side, engulfing the Mach disk of initial jet. The incident shock waves of gunpowder gas jet undergo Mach reflection on the bottom wall of projectile at 210μs, followed by Mach reflection occurring twice near the central axis, leading to the formation of a bottle-shaped shock wave structure with double three-wave points. The displacement of Mach disk in the gunpowder gas jet demonstrates an exponential attenuation pattern over time, while the diameter exhibits a trend of “growth-sudden increase-stability”.

Key words: underwater launch, muzzle flow field, shock reflection, bottle-shaped shock wave, Mach disk

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