Influence of Different Velocities on Muzzle Flow Field

A two-dimensional axisymmetric numerical simulation was successfully carried out on the muzzle flow field of a 300 mm-caliber counter-mass propelling gun. Based on the FLUENT software, using the finite volume method (FVM)and the realizable k-ε turbulence model, we adopted the holistic movement of a partitioned mesh processing method coupled with the intermediate ballistic model and the six degree-of-freedom model(6-DOF). We compared the flow field characteristics at the velocity of 1 730.4, 978.3, and 323.4 m/s. The results indicate that the pressure of the hypersonic initial flow field is much higher than that of the subsonic and supersonic initial flow fields. In the case of the subsonic(323.4 m/s) flow field, the tiny disturbance spreads throughout the whole domain. But in the cases of the supersonic (978.3 m/s) and the hypersonic (1 730.4 m/s) flow fields, it cannot spread to the upstream disturbance source, and the disturbance domain of the supersonic flow field is wider than that of the hypersonic. It is noted that the subsonic flow field has a rounded shock wave before the projectile. However, in the supersonic and hypersonic flow fields, a shear layer is formed which begins from the head of the projectile and extends outward from the side of the projectile. Then a multi-layer shock wave is formed composed of coronal shock waves, bottom shock waves, reflected shock waves, and Mach disk. © 2019, Editorial Department of Transactions of NUAA. All right reserved.