Analysis of muzzle flow field characteristics of gun fired in different media

Abstract

To study the muzzle flow field created by a sealed launch of an underwater gun and the distribution characteristics of the muzzle flow field in different media, a two-dimensional axisymmetric numerical model for the muzzle multiphase flow created by an underwater sealed launch is established. The volume of fluid numerical model, standard k- \begin{document}$\varepsilon $\end{document} turbulence model, user-defined function (UDF) and dynamic mesh technology are used to numerically analyze and compare the evolution process of the muzzle flow field between underwater sealed launch and air launch. The calculation results show that the muzzle flow field is notably different from that in air when the gun is launched under water. The maximum chamber pressure of the underwater sealed launch is basically the same as that in air. The muzzle velocity of the projectile is reduced by 32 m/s compared with launching in air, while the pressure and temperature of the muzzle are significantly increased. The Mach disc of the underwater sealed launch is initially formed at about 140 μs, while the Mach disc of the air launch is formed later, at about 320 μs. Compared with launching in air, the core area of shock wave in underwater launch is smaller, and there is no coronal shock wave around the head of the projectile. In the case of underwater sealed launch, the axial displacement of the Mach disc from the muzzle increases exponentially with time, while in the case of air launch, the axial displacement of the Mach disc from the muzzle increases linearly with time.