膛口初始流场对火药燃气射流的影响

身管武器发射弹丸时,初始流场对随后火药燃气射流的发展及弹丸的运动有较大的影响。为了分析初始流场对燃气射流结构以及弹丸运动的影响,基于有限体积法,采用分块网格划分的整体运动方法及Realizable k-ε湍流模型,耦合内弹道过程及六自由度方程,建立了含有初始流场和不含初始流场的两种二维轴对称膛口流场数值模拟模型。以300 mm平衡炮为例,研究了1730 m·s~(-1)发射速度下的膛口流场特性。结果表明,无初始流场时,火药燃气波阵面近似为球形,火药燃气无法追赶上弹丸。而在初始流场的干扰下,膛口喷射出的燃气速度提高约200 m·s~(-1),燃气追赶并包围弹丸,流场中最大压力降低一倍,温度提高1000 K以上,弹底压力降低约1.3 MPa。

Effect of Precursor Flow Field of Muzzle on the Combustion Gas Jet Flow of Gun Propellant

When the projectile was launched by a barrel weapon,the precursor flow field had greater impact on the development of combustion gas flow of subsequent propellant and the movement of projectile.To analyze the effect of precursor flow field on the structure of combustion gas jet and movement of projectiles,based on the finite volume method,two different 2-d axisymmetric numerical models with and without the precursor flow field were established using the Whole Zone Movement Method for block grid division and Realizable k-ε turbulence Model and coupling the interior ballistic process and the Six-DOF equations.Taking the 300 mm counter-mass propelling gun as example,the muzzle flow field characteristics at the ejection speed of 1730 m · s-1 were studied.The results show that when there is no precursor flow field,the wavefront of propellant combustion gas is approximately spherical,and the propellant combustion gas is unable to catch up with the projectile.But under the interference of precursor flow field,the ejectingn velosity of propellant combustion gas increases by about 200 m·s-1,and the combustion gas catches up with and surrounds the projectile,the maximum pressure in the flow field decreases by a half,the temperature increases by more than 1000 K and the projectile base pressure decreases by about 1.3 MPa.