Numerical Simulation And Optimization Design On Interior Ballistic Performance Of Light Gas Launcher

In this paper,using two-stage light gas gun as the engineering research background,A mathematical physics model for interior ballistics of two-stage light gas gun was established,and its interior ballistic process was simulated numerically and optimized.The main research contents are as follows:(1)According to the launching feature of two-stage light gas gun,classical interior ballistic model was used to describe combustion of powder in chamber and piston motion,and one dimensional unsteady compressible fluid model was used to describe flowing of gas in light gas chamber and projectile motion.The two parts were coupled together through piston motion to develop a mathematical model for interior ballistic launching process of two-stage light gas gun.(2)The basic equations in powder chamber were solved numerically with the fourth-order Runge-Kutta method,and the control equations in light gas chamber were solved numerically with the second-order MacCormack scheme.The numerical simulation for interior ballistics process of 30mm/120mm two-stage light gas gun was accomplished by alternation between these two computations.The model established is validated rational according to the simulation results.(3)In order to analyze the effects of different emission parameters on launching performance of two-stage light gas gun,especially projectile muzzle velocity,the emission parameters were changed,including charge weight,initial gas injection pressure,piston mass,projectile mass,piston start pressure and projectile start pressure.The results provide theoretical references for parameters design and improvement of launching performance of two-stage light gas gun.(4)On the basis,under the maximum pressure constraints in powder chamber and light gas chamber,an optimization design model for interior ballistics of two-stage light gas gun was established by taking the maximum projectile muzzle velocity as objective function,with charge weight,initial gas injection pressure and piston mass as design variables.The interior ballistics of 30mm/120mm two-stage light gas gun was optimized with real-coded genetic algorithm,and a better optimal result was obtained by the optimization.The optimal result shows that genetic algorithm has a satisfactory convergence in the optimization design for interior ballistics of two-stage light gas gun.