Study on interaction characteristics between multi gas jets and water during the underwater launching process

To further understand the mechanism of new submerged water piercing gun launcher, the simulation device of an imitated projectile is designed with using multi combustion gas jets to drain off the water in gun tube. The expansion characteristic of multi gas jets and generation mechanism of the gas-curtain in the liquid medium are experimental observed by a high speed camera. The experiment shows that, with the mixing process between the multi combustion gas jets and the liquid medium, the gas-curtain is generated, which provides a gas path for the projectile motion. On the base of experimental observation result, the influences of injection pressure and sprayer structure on projectile motion are discussed. Experiment result indicates: increasing injection pressure, both axial expansion velocities of gas-curtain and projectile moving speed increase; magnifying the center nozzle cannot enhance the drainage performance of the gas-curtain and will restrain projectile motion in the later stage; with enlarging the oblique plane nozzles, the axial velocity of gas-curtain tend to rise after converging and projectile kinematic performance is also improved.