Stage Light Gas Gun Interior Ballistics Simulation Study

Two-stage light-gas gun is a firing system which can obtain high velocity of projectile by high temperature and low molecular weight medium expanding to force projectile moving. It is a kind of universal high speed launching tool. In order to research the effect of two-stage light-gas gun parameters on the launching performance, the interior ballistics process is analyzed.According to the characteristics of the two-stage light-gas gun firing process, the classical theory of interior ballistics is employed to describe the combustion of powder in chamber and the movement of piston, and the mathematical model for compressible unsteady quasi-one-dimensional flow is employed to describe the flow pattern in light-gas chamber and the movement of projectile. These two groups of equations are coupled together by the movement of piston to describe the whole launch process of two-stage light-gas gun. The former equations are solved numerically with the classical Rung-Kuntta method, and the latter equations are solved numerically with the second-order MacCormack scheme. The computation of the whole launch process of the two-stage light-gas gun is accomplished by alternation between these two computations.Based on establishing the mathematical model of launching process of two-stage light gas-gun and numerical calculation, the theoretical computation is accomplished. A 30mm/100mm two-stage light-gas gun is taken for the primary computing model, and lots of data are obtained by computing the model under different geometry parameters and different loading conditions. On the basis of the results of analyzing systematically, some laws of the effects of geometry parameters and loading conditions on the launching performance of two-stage light-gas gun are obtained, which laid a good foundation for further research.