水下弹射筒口气泡及载荷特性数值研究

The gas bubble and loads near the launch canister outlet are important for the safety of structures during underwater ejection launching. In order to clarify the bubble evolution process and load characteristics of a barrel of missile underwater ejection which is widely concerned at home and abroad. The computational fluid dynamics(CFD)of the Reynolds average Navier-Stokes(RANS)method and dynamic mesh method are employed to establish numerical model of unsteady two-phase flow, and simulate the underwater ejection flow field of triple-launch system after data verification by experimental measurement. The results show that working fluid gas of underwater ejection has significant impact on the outlet in the separation of missile and canister. After that, the bubble formed by the missile working gas at the nozzle experienced expansion development, interfacial condensation fracture, and compression contraction of the trapped bubble at the nozzle, and accompanied by the expansion and contraction process, alternating load impact is generated on the surrounding equipment, and the load variation amplitude exceeded the pressure difference between internal and external the canister when the projectile body is removed from the canister. The minimum pressure can be reduced to 0.7 times of the environmental pressure and the maximum pressure can be increased to 1.5 times of the environmental pressure at the water tight film position adjacent to the launching position of triple-launch system. It is an important part of anti-shock design of equipment.