Study On Performance Of Portable Missile Interstage Piston-type Separation Device

The inter-stage piston-type separation device of portable missile is a kind of inter-stage separation device with simple structure and reliable performance.In this paper,the working process of the device is simulated by Simulink simulation software and linear dynamic analysis software LS-DYNA,and experiments of launch engine were carried out to verify.The main contents are as follows:Firstly,mathematical models of the internal ballistic and the pressure of piston cylinder are established,and the simulation model of the pressure of launch engine and the pressure of piston cylinder is established by using the Simulink simulation software.The time curve of the air flow and the pressure time curve of the piston cylinder are obtained.Research results show that:During the working-stage of launch engine,the pressure of the piston cylinder is gradually increased,and reached the equilibrium pressure at t=31.2ms.In the filling stage of piston cylinder,the flow of air experiences three stages of non critical flow rate increasing sharply and critical flow rate rating constant and non critical flow rate decreasing gradually.In the exhausting stage of piston cylinder,the flow of air experiences two stages of non critical flow rate increasing sharply and non critical flow rate decreasing gradually.Secondly,the influence of piston cylinder volume and air hole diameter on the characteristics of piston cylinder is analyzed.Research results show that:in the case of the other parameters of the launch engine,the time of aeration is proportional to the volume of the piston cylinder,and the piston cylinder volume has a critical value.The cylinder volume is close to the critical value,the pneumatic separation characteristics of the piston-type separation device are better.The time of aeration is proportional to the critical diameter of air hole,and critical diameter of air hole has a critical value.The critical diameter of air hole is close to the critical value,the pneumatic separation characteristics of the piston-type separation device are better.Thirdly,through the establishment of the shear force simulation model,the shear force time curve is obtained.To establish the simulation model by using LS-DYNA onthe dynamic process of the shear pins,through the simulation analysis,obtained the shear pins time.Studies have shown that during the launch engine tail section,shear force rose sharply to the maximum,and guarantees the reliable shear pin connection in a wide range of pin.Simulation model is established by using LS-DYNA software on the dynamic process of the shearing pins and through the simulation analysis,the time of shearing pins is obtained.During the falling-stage of launch engine,shearing force increases sharply to the maximum,and can ensure shearing pins reliably in a wide strength range of connection pins.Fourthly,a simulation model for the separation of the piston-type separation device is established,and it is verified by experimental engines and test engines.The results show that:The simulation results are in agreement with the experimental results and numerical simulation and calculation is feasible.Temperature environment has a great influence on the separation between the two stages,and the higher the environmental temperature is,the shorter the time of the separation.