Load-Reducing Characteristics of Gas Screen During Underwater Launch of the Vehicle

Abstract

During the underwater launching process, a gas screen channel is formed near the opening of the cylinder, which can effectively reduce the high-frequency pulsation load on the surface of the vehicle exiting the cylinder. Based on the volume of fluid (VOF) homogeneous multiphase flow theory, the standard RNG k-ε turbulence model, and the overlaid grid technology, this paper studies the influence law of the gas screen on the surface of the vehicle to improve the pulsating load of the vehicle, and analyses the flow field structure and hydrodynamic evolution under the gas screen environment. The characteristics of the gas curtain flow field structure evolution and the discharge load reduction effect at different cross-flow intensities and gas mass flow rates were compared. The results show that the high-speed gas ejected from the nozzles approximately covers the surface of the vehicle during the exiting process, and gradually forms a gas channel around the opening of the launch vessel, thereby reducing the surface load of the vehicle significantly. Under the condition of gas screen, both the moment and the surface load on the body have been significantly reduced, with the peak value of the moment reduced by 80.3%, and the peak pressure on the surface of the vehicle reduced by 81.2%. However, the peak pressure on the surface of the vehicle increases by a maximum of 56.7% upon increasing cross-flow intensity. Finally, the mass flow rate increases from 2 kg/s to 16 kg/s, with the moment on the vehicle reduced by 80.8% and the peak surface pressure reduced by 82.8%.

Keywords

• vehicle
• multiphase flow
• pulsating load
• gas screen load reduction
• hydrodynamic characteristics