Research on the Dynamic Inflation Characteristics of the Large-Size Gasbag with Multiple Nozzles Based on the Fluid-Structure Interaction Method

To meet the needs of the airborne dispenser to disperse large-mass bullets, the dynamic inflation process of the large-size gasbag with two nozzles and three nozzles is numerically simulated and analyzed using the fluid-structure interaction method. The calculated final expansion shape of the gasbag is in good agreement with the experimental results. According to the changing law of the expansion velocity, the dynamic inflation process of the gasbag can be divided into three stages in which the gas shock, the pressure in the gasbag and the stress on the gasbag wall are respectively the main factors affecting the expansion of the gasbag. Under the same propellant charge, there is a phenomenon of hysteresis in the expansion height and the expansion velocity of the gasbag with two nozzles. The pressure in the gasbag with three nozzles is higher and more evenly distributed. Therefore, the final expanded shape of the gasbag with three nozzles is fuller than that of the gasbag with two nozzles. However, this also leads to a more serious deformation of the folds on the end surfaces of the gasbag with three nozzles, and the maximum stress at the folds is 824.5 MPa greater than that of two-nozzles gasbag.