Numerical simulation research on coupling of gas generator with large aspect ratio and multi-vent

Abstract

The pressure distribution of the combustion system with a large aspect ratio is uneven, and the process of gas flowing out through the vent holes arranged along the axial direction is inconsistent. Therefore, a multi-vent gas generator was designed and experimented. The experimental results show that the vent holes of each group arranged along the axial direction can be opened simultaneously. Based on the explicit dynamics method, the finite element model of the gas generator is established. The interior ballistic program is used to calculate the pressure field, and ABAQUS is used to simulate the structural dynamics. These two are coupled and solved through the subprogram interface VUAMP. The coupled calculation results show that the simulated values are in good agreement with the experimental values, which verifies the accuracy of the coupled model. The response time and opening time of the vent holes decrease with the increase in the propellant mass. The force analysis of the axial motion process is carried out. In the early stage, the frictional resistance and gas thrust rise concurrently with the improvement of gas pressure, but the influence of the former gradually diminishes compared with the latter. In the later stage, the impact of reaction force provided by rubber cushion is greater than that of gas thrust and frictional resistance. The maximum compression deformation of rubber cushion is less affected by the propellant mass, which effectively plays the role of buffering and braking.