Stability And Reliability Research Of Supercavity Vehicles

The supercavity vehicle is an underwater high-speed weapon which is enwraped by the supercavity. The supercavity is the cavitated phenomenon, i.e. cavity. The boiloff of water have two methods, one is to increase the temperature of water, another is to depress the press. The front method is called evaporation or boil, and the behind method is called cavity. When the vehicle moves fleetly, the press depresses consumedly, and the vacuum negative-pressure can be produced sometimes. At this time, although the water is normal temperature, the water can boil, and low-press air bubble can be produced (water can boil under 0.02 atmospheric pressure ). Those air bubbles blow up rapidly by the effect of the environmental water press, and powerful bow wave is produced also. This is the cavitated phenomenon.The moving status of supercavity vehicle is so complex, and the stabilization moving of supercavity vehicle is a very important question. If the supercavity vehicle is analyzed in the status of non-stabilization only by the common confirm mechanics method, and the randomicity of environment is not calculated, it stand a good chance that the supercavity vehicle can not move steadily, and it can not attain the high-speed request. Therefore, it is more practical in the engineering that the supercavity vehicle is analyzed in the status of stabilization.The mostly content of this paper is,1) The basic theory of supercavity vehicle is researched, and boundary value of supercacitation is analyzed, therefore the suppose of the supercavity mathematics model. The steady moving of supercavity vehicle is researched by the method of added masses, and the force of steady moving is calculated by the method of plane sections. The schemes of the supercavity closure is analyzed, and gained six closure schemes. The radius and resistance coefficient of supercavity is gained by the engineering predigestion method. 2) The bend problem of the axes of cavity is researched when supercavity vehicle moves steadily. The reason of the bend problem of the axes of cavity is produced by the attack angle of cavitator and the gravitation. And, the axes of cavity bended by the attack angle of cavitator is introduced minutely.3) The steady moving of supercavity vehicle is researched. The coordinate is built in order to analyze supercavity vehicle moving steady. The force expression of the empennage of supercavity vehicle is given, the expression of the force and the moment when supercavity vehicle moves steadily is gained. In the end, the connection of every angle is given.4) Reliability research. Firstly, the characteristic and calculate step of the finite element method and Monte Carlo method are introduced, then the force of cavitator and engine is calculated by the program, and the connection of angle is gained. The model is built according to the examination of our university. The pretreatment of finite element is processed by the finite element method, and the reliability analyze is processed by the Monte Carlo method. In the end, the reliability index is gained.