Research On Gas And Liquid Flow During The Process Of Cavity Exhaust Of Underwater Vehicle

As a kind of underwater weapons,submarine-launched vehicle with excellent concealment,mobility and attack capability,has attracted attention of more and more countries around the world.Deep-water launch of the submarine-launched vehicle surface is equipped with exhaust vent,in the process of vertical launching and floating of water,the pressure of the surrounding environment is gradually reduced,and the pressure difference between the cavity and the external environment of the vehicle makes the gas in the cavity constantly discharged through the exhaust hole,which is known as the cavity exhaust phenomenon.Cavity exhaust is a kind of cavitation flow,including unsteady,turbulent and gas-liquid two-phase interaction.The improper design of the exhaust hole may cause the high-pressure gas is not timely exhaust or the water intrusion,affecting the safety of the structure,interfering with trajectory characteristics in water or damage to internal instruments.With the increasing demand of launching in deeper water,the study of gas-liquid flow characteristics in the process of cavity exhaust is helpful to optimize the hydrodynamic and trajectory stability of underwater vehicle,and provide reference for practical engineering application.The main research contents and achievements are as follows:The experimental method and the numerical calculation method of the gas-liquid flow characteristics of the cavity exhaust process is established.The cavitation test model,the anti-cavitation model support and the gas-liquid characteristic test system are designed and developed.At the same time,based on the basic equation of the equilibrium flow model,the turbulence model and the basic,the numerical simulation method of gas and liquid flow characteristics during the exhaust process of the vehicle is established,and the results are compared with the results of experiment,so as to verify the validity of the numerical simulation method.The gas and liquid flow characteristics of the cavity exhaust process of the vehicle under different flow field parameters were studied.The mass flow rate,the cavity shape,the model surface pressure and the model resistance were analyzed.When the exhaust hole is exhausted,the larger the initial pressure ratio is,the smaller the width of the first half of the test model and the more obvious the edge fluctuation.Exhaust gas causes two peak values on the surface pressure of the model,and the larger the initial pressure ratio is.The gas and liquid flow characteristics of the cavity exhaust process of the vehicle under different structural parameters were studied.The mass flow rate,the cavity shape,the model surface pressure and the model resistance were analyzed.When the exhaust hole is flooding water,the change of the angle of attack has little effect on the water mass flow.The larger the hole diameter is,the higher the mass flow rate is,and the mass flow increases with the increase of the hole diameter.When the exhaust hole is exhausted,the larger the model angle is,the smaller the cavity width is,and the necking phenomenon occurs at the front of the bubble.The larger the hole diameter is,the larger the peak of the pressure of the model.