Numerical Simulation And Optimization Of Interior Ballistic Processes In The Three-Stage Light Gas Gun

Light gas gun is hypervelocity launching technologies used on the hypervelocity impact test, its muzzle velocity of the projectile directly affects the imapacted material’s high pressure, high strain rate, high temperature.Light gas gun’geometry and launch parameters are the main affected factors of Light gas gun’interior ballistic process and projectile velocity.This paper uses hypervelocity light gas gun as background,and makes a series of numerical simulations on the two-stage light gas gun and three-stage light gas gun,then analyzes its interior ballistics process. The main parts of this research are concluded as follows:a) The launching principles and interior ballistics processe of two-stage light gas gun and three-stage light gas gun are analyzed, the classical interior ballistic theory in the chamber is established,and fourth-order Runge-Kutta scheme is used to simulate the power chamber. Two-dimensional axisymmetric unsteady compressible model is established in the light gas chamber,Spalart-Allmaras one equation turbulence model and AUSM+scheme are used in the numerical simulation.The classical interior ballistic program is coupled into UDF,then interfaced with Fluent,finally interior ballistic program coupled into light gus chamber program is realized.b) Variations of chamber pressure,piston motion, light gas chamber pressure, projectile motion, shock propagation are obtained after the numerical simulation. In order to analyze different factors affecting the interior ballistic process and the emission performance,the geometry and emission parameters of two-stage light gas gun are changed in the numerical simulation,such as piston mass, projectile mass, the initial injection pressure of gas, pump tube diameter, projectile start pressure, etc.c) Variations of chamber pressure, one-stage piston motion, two-stage piston motion one-stage light gas chamber pressure, two-stage light gas chamber pressure,projectile motion, shock propagation are obtained after the numerical simulation.In order to analyze different factors affecting the interior ballistic process and the emission performance,the geometry and emission parameters of three-stage light gas gun are changed in the numerical simulation,such as one-stage piston mass, two-stage piston mass, projectile mass, the initial injection pressure of gas, two-stage pump tube diameter, projectile start pressure, etc.