Groove structure on the drainage characteristics of the gas curtain

Abstract

The high resistance caused by water in the barrel during the underwater launch poses a daunting challenge to launch safety. To solve this problem, a new method is proposed to form a gas curtain based on the principle of the gas-curtain launcher. The key to the method is setting up several rectangular grooves on the barrel inner wall to guide the gas flow and form a gas curtain. A three-dimensional unsteady model is established to simulate the formation of the gas curtain under different aspect ratios of the grooves. The simulation results show that as the aspect ratio increases, the convergence effect is weakened, the drainage effect is gradually improved in the near-wall region and decreased in the center of the tube. With the increase of the aspect ratio, the pressure around the projectile head increases, the high-pressure region expands in the initial stage of jet expansion and the region of pressure fluctuation is reduced in the latter stage. When the aspect ratio increases from 0.625 to 1.6, the average drainage mass per unit time is increased by 3%, and the gas efficiency-cost ratio is increased by 6%.