The effect of a composite buffer chamber structure on the interior ballistic performance of a gas-driven launch system

Gas-driven launch stands as a core enabling technology for realizing rapid space response and precise attitude adjustment of spacecraft, thereby exhibiting substantial application potential in the field of aerospace engineering. To address the dual requirements of high-pressure stable combustion and low-overload launch during propulsion, this study proposes and investigates a gas-driven system with a composite structure: a stable combustion environment is constructed via the synergistic design of a high-pressure chamber and a buffer chamber, while the low-overload launch target is accomplished relying on a multi-stage drive architecture. To verify the rationality of the system, a ground experiment prototype was developed, and a multi-parameter synchronous testing system was established, by which key performance indicators, including pressure, thrust, and launch velocity, were measured. Meanwhile, a numerical simulation method for two-phase flow in multi-stage series interior ballistics was constructed to finely describe the spatiotemporal distribution characteristics of the chamber flow field. Experimental and simulation results demonstrate that: the peak pressure of the high-pressure chamber reaches 77.46 MPa, whereas the peak pressures of the low-pressure chambers are all constrained within 7.1 MPa, successfully fulfilling the design objective of high-pressure combustion with low-pressure propulsion, the maximum error of key parameters between numerical calculations and experimental tests is merely 6.49%, and the theoretically calculated pressure curves are in good agreement with the measured ones in terms of variation trend, which validates the reliability and accuracy of the established numerical model. Based on the validated numerical model, parametric performance prediction was conducted to systematically investigate the effects of buffer chamber orifice size and the number of holes in the high-pressure chamber partition board on launch performance. The results indicate that the system achieves optimal launch performance when adopting the structural parameter combination of a double-hole high-pressure chamber outlet and a 5 mm buffer chamber outlet. This finding provides a theoretical basis and technical reference for the structural optimization design of similar gas-driven systems.