Study On The Dynamic State Of The Piston Entering The Cone Of The Two-Stage Air Gun

Air gun is one of the ultra-high-speed launching devices for high-speed impact test.In order to achieve an ultra-high-speed launching,the high-temperature and low-molecular-weight gas is used to push the piston in the pump tube.Therefore the two-stage air gun is used as a kind of launching device which coupling the first-stage air gun through the high-pressure cone section and the piston.In order to achieve the piston entering into the cone smoothly,the movement of the piston in the high-pressure section was comprehensively in this paper.In order to make the experimental results are closest to the simulation results,the parameters of the simulation is modified reasonably.This paper deals with the basic composition and operating principle of the two-stage air gun and launches the dynamic model of piston entering cone and the first-stage air chamber.Matlab software is used to program the movement of the piston in the pump pipe and high pressure cone section.This paper determines the two sets of other launch parameters of the two-stage air gun based on the diameter of the launch tubeΦ10mm and pump tubeΦ57mm.According to these launch parameters,curves of the piston are drawn in this paper,such as speed-time curve,the pressure on the right side-time curve,the stroke-time curve.The influence of factors such as high-pressure section’s taper,piston’s quality,tube’s pressure,first-stage gas’s type and first-stage gas’s pressure are discussed comprehensively in this paper.According to the technical requirements of the two-stage air gun,the dynamic parameters of the piston which entered the cone are tested.Through the comparison between the experimental results and simulation results,the parameters of the simulation is modified reasonably.When the k₀ and k₁of the first-stage dynamic model and the dynamic model of the coning process are taken as 1.4,the experimental results are closest to the simulation results.Based on above results,design basis for test system is provided reasonably.