Research on multiphase flow field characteristics of underwater gun double‐tube parallel firing

Abstract

The underwater muzzle flow field formed by the double‐tube launch will interfere with each other, resulting in large changes in the characteristic parameters of the flow field and shock wave morphology. Therefore, the numerical model of three‐dimensional unsteady multiphase flow for underwater gun‐sealed launching was established. Meanwhile, an experimental platform for the underwater sealed launch was built and the rationality of the model was verified. The interior ballistic process compiled by UDF was coupled with the dynamic mesh technology, and the VOF multiphase flow model integrated with the Schnerr‐Sauer cavitation model was chosen to numerically calculate the muzzle flow field of the 30 mm underwater gun double‐tube parallel launch, and the numerical results were compared to those of the single‐tube launch. The results show that the gas is expelled from the muzzle and rapidly expands to form a gas cavity, and the “necking” phenomenon of the gas cavity occurs at 0.2 ms, while the Mach disk structure has formed. Due to the mutual interference between the flow fields formed by each tube, the diameters of the Mach disk are slightly different, and the flow field structure has a certain asymmetry in the evolution process. The core area of the shock wave is bowl‐shaped of the single‐tube launch, while it is not completely filled of the double‐tube launch. Within 0.5 ms, the diameter of the Mach disk increases monotonously when the single‐tube is launched, while it first increases and then decays by a double‐tube.

Modeling and Optimization of Interior Ballistics within Pneumatic Underwater Launchers

“…Since the launching process is isentropic, the mass flows through the launching valve can be obtained from ( 6) and (7):…”

“…Gao, S. et al [6] investigated the vortex structure and trajectory parameters of the wake of an underwater launch vehicle using an enhanced delayed separation vortex simulation, a VOF multiphase flow model, and an overlapping grid approach. A three-dimensional unsteady multiphase flow numerical model was established by Zhang, X. et al [7] for the sealed firing of an underwater gun. The VOF multiphase flow model was chosen and integrated with the Schnerr-Sauer cavitation model.…”