Modeling and validation of high-speed pneumatic system for interstage separation

Rocket interstage separation is essential for successfully placing a payload into orbit. The substantial mass and high-speed separation between the stages demand an effective pneumatic separation device, crucial for booster recovery and reuse. To verify the feasibility of such a device, a high-speed pneumatic system is developed and a real gas dynamic model for the cylinder movement process is created. The model is based on the structure and technical requirements of the single-acting separation device, and also the Van Der Waals gas equation of state for high-pressure gases. The thermodynamic properties of each high-pressure gas cavity of the system are analyzed. The cylinder movement in the interstage separation process is derived and verified from the theoretical model level. MATLAB/Simulink is applied to model the pneumatic system and analyses the gas characteristics in the system, cylinder movement process and so on. The simulation results achieve a separation speed of 4.15 m/s, a separation time of 0.43 s, and an average actuating thrust of 238.6 kN, which satisfy the separation performance index. The results can be used as the theoretical basis for the application and analysis of high-speed pneumatic system in the interstage separation of launch vehicles. It provides a certain reference for pneumatic system verification and is expected to be used in aerospace.