Numerical Simulation on Field Characteristics of the Horizontal Gas Jet Flow of Underwater Vehicle

Solid rocket motors are important for the propulsion of underwater vehicles, especially for rapid maneuvering. To study the characteristics of the gas jet flow field generated by the engine of the underwater vehicle, a numerical calculation model considering gravity and phase transition was established. The basic laws of formation and evolution of jet bubbles were studied, and the unsteady characteristics of the jet flow field considering phase transition and the influence of inflow velocity and attack angle on the jet were analyzed. The results show the gas bubbles successively take on “concave” and “convex” shapes, and there exist “rebound” and “nesting” phenomena after the gas is accelerated and injected into water by the nozzle; the engine considering the phase transition process can obtain larger momentum and the degree of pressure fluctuation becomes smaller, which contributes to improving the propulsion efficiency of solid rocket motors by adding the gas-liquid phase transition model; the inlet flow has an inhibitory effect on the pressure pulsations of the flow field, and the influence of the wake on the vehicle which adopts rocket assist decreases as the speed increases; the upward deflection of the gas bubbles intensifies and the rupture of gas bubbles become closer to the nozzle outlet as the attack angle increases.