Three-dimensional particle-scale investigation of transient gas–solid flow characteristics in the propulsion system with a complex charge structure

This work is focused on researching the particle behavior of the transient gas–solid flow in the propulsion system with the modular charge structure, which has a great effect on the temporal-spatial distribution of energy release. Based on the coupling method of computational fluid dynamics and the discrete element method, an efficient three-dimensional unsteady gas–solid model is developed to provide a detailed means of capturing particle behavior in the propulsion system with a complex structure. Comparisons of the particle distribution of simulation results are done with experimental research, and a reasonable match has been obtained. Furthermore, the particle behavior characteristics can be divided into three stages. In the first stage, the particle behavior is dominated by the high-pressure, high-speed gas from the igniter. In the other two stages, the particle behavior is dominated by the complex gas flow generated by the opening of the module and the groove structure of the vehicle. The results show that the distribution of particles consists of slope accumulation and horizontal accumulation. The slope accumulation with a large gradient contains 84% of the total particles, and the height of the slope accumulation is increased exponentially along the axis.