Abstract: The overpressure of shock wave is widely used in opening the launching canister. In order to study the formation of shock wave and its effect on the fragile lid with a nozzle closure, a simulation model is established by using a numerical method, in which a dynamic mesh technique is used to update the meshes of flow field. The simulation results are verified with the experimental results. The formation process of jet flow is shown clearly and the changing curves of the overpressure on the back lid with time are obtained from the analysis results. The research results show that the overpressure of shock wave forms on the nozzle closure and then impact the fragile lid. The gas converges from the edge of nozzle closure to the center to form a mainstream. The effects of the mainstream and the shock wave on the back fragile lid are obviously different in impact time and position. The back fragile lid is brittlely deformed under the action of overpressure of shock wave. In the projection area of the nozzle closure, the instantaneous peak first reaches to the maximum value of 5×10⁵ Pa.

Key words: ordnance science and technology, nozzle closure, shock wave, fragile lid, numerical simulation