Ignition process and propellant grains distribution of the two-module charge

Abstract

The accumulation form of propellant grains has a great effect on the initial chamber pressure wave in the ignition and flame-spreading process of a modular charge. In this process, the grains distribution is determined by the dynamic characteristics of grains after the cartridge is broken. Therefore, a visualized ignition simulation experimental device was designed for the ignition test of the two-module charge with different initial loading positions. A high-speed camera system was used to observe the ignition and flame propagation, the rupture of combustible cartridge cases, and the moving process of the propellant grains. The experimental results show as follows. When the two-module charging position is far from the primer and the spacing between the two modules is increased, the time of flame propagation in the chamber is prolonged. And the cartridge cases are more completely burned and their rupture areas become larger. The propellant grains in the chamber are finally scattered in the axial 195–500 mm area starting from the end face of the primer side. The grains are mainly distributed in the steep-slope accumulation on the right side of the chamber. On the basis of the experiment, a three-dimensional unsteady gas-solid two-phase flow model for the modular charge was established. The dynamic process and distribution of the propellant grains was simulated. The calculation results are basically consistent with the test ones, which validate the rationality of the established model.