Research On Key Technology Of Shipborne Large Caliber Underwater Defense Projectiles

At present,the torpedo is still considered as one of the most dangerous weapons to the surface ships in the modern marine military operations,and most of the modern torpedoes have strong underwater acoustic resistance and self guidance ability,especially when the torpedo is close to the target,the probability of surface ships relying on the traditional non lethal and soft lethal means to avoid the torpedo attack is getting smaller and smaller,so Hard kill means will certainly become an important means of short-range anti torpedo for surface ships.The active H/PJ38 single tube 130 mm naval gun is the main gun of naval surface ships in our country.Because of its excellent fire control system and automatic loading technology,it is far faster than the ground gun in terms of firing speed.If the characteristics of high firing speed of the naval gun are applied to the short-range anti torpedo operations,large-scale barrage can be formed near the torpedo trajectory in a short time to seal the torpedo In order to achieve this goal,the high requirements are put forward for the launched projectile.As we all know,ordinary grenades are very difficult to enter the water,and they are very easy to jump at the moment of water collision.Even after entering the water,the underwater trajectory is not stable.Therefore,first of all,it is necessary to ensure that the projectile has good water entry stability and underwater ballistic performance;second,it is required that the projectile is empty The good aerodynamic characteristic is the precondition for the projectile to have the best attitude into the water.Finally,the projectile is required to be able to damage the target efficiently.Based on the above requirements,aiming at the problems existing in the water entry trajectory,air trajectory,terminal damage and other aspects of the shipborne large-diameter underwater defense projectile,this paper takes theoretical analysis as the basis and numerical simulation as the means to conduct in-depth research on the key technologies of the projectile in each stage,and the specific contents are as follows:(1)According to the requirement of tactical index and the reference of foreign large caliber supercavitating projectiles,the overall scheme of projectiles is designed preliminarily by using the centroid ballistic equation,which mainly includes the determination of the general structure and shape of projectiles,the determination of the material and loadingquality of each part of projectiles.(2)According to the research and analysis of the process of projectile entering the water,because of the high speed of projectile entering the water,supercavitation will occur in the later stage of water entering.Therefore,firstly,theoretical analysis of cavitation phenomenon and stress situation is carried out,and then the influence of projectile center of mass and structure of cavitation device on the water entering stability is studied by using ABAQUS finite element simulation software,and finally the best water entering stability is obtained The structural shape of the projectile.(3)By using ANSYS/CFX hydrodynamics analysis software,the aerodynamic simulation analysis is carried out for projectiles with good water inflow stability,the aerodynamic parameters under multiple attack angles and Mach numbers are calculated,the aerodynamic characteristics of projectiles are studied,and the minimum conditions for the projectiles to have flight stability are obtained.Finally,the external trajectory of projectiles is calculated by using the external trajectory program.According to the calculation results,the projectiles in flight 5 are verified After km,can it still have a good water entry speed and attitude.(4)Using AUTODYN finite element simulation software to simulate and analyze the relevant laws of underwater explosion of projectiles.Firstly,the influence of shell thickness on the distribution of overpressure of underwater explosion is studied,then the influence of water depth change on the distribution of overpressure is studied.Finally,the distribution of overpressure of multiple projectiles at the same time underwater explosion is studied.