Numerical Simulation of Underwater Gas Jet Fields with the Continuous Change of Ambient Pressure

Abstract

Deep-sea antisubmarine missiles undergo significant changes in water depth during underwater navigation. It is of great importance to study the structure of the gas jet and working characteristics of the underwater solid propellant rocket engine of antisubmarine missiles during continuous changes in environmental depth pressure. Utilizing the volume of fluid (VOF) multiphase model, this study combines the user-defined function (UDF) with the dynamic mesh technique to establish an axisymmetric dynamic model of an underwater solid propellant rocket engine, as well as simulates the process of vertical motion of the underwater engine to a depth of 250 m. The results show that the gas jet no longer breaks and strikes back at the end of the nozzle during underwater motion. During the formation of the supersonic jet, the shock wave is gradually pushed out of the nozzle outlet, and finally, a conical shock wave with a fixed position is formed. Below a depth of 100 m, the flow field characteristics of the gas jet are significantly affected by the ambient pressure, and the flow field structure shows apparent compressibility. At a speed of 200 m/s, the gas jet obstruction effect is weakened, which reduces the effect of the ambient pressure on the working characteristics of the underwater engine. The study of the flow field characteristics of underwater gas jets subjected to continuous changes in ambient pressure can provide a reference for exploring the working performance of underwater engines in deep-water vertical motion.

Keywords

• antisubmarine missile
• underwater solid propellant rocket engine
• gas jet
• ambient pressure
• dynamic mesh technique