Development of mixed modeling method to obtain parameter distributions in a high-speed propulsion combustion system

The gas–solid flow state of the high-speed combustion system varies with the propellant combustion and the movement of the projectile. In this paper, to accurately obtain the motion characteristics and flow field distribution in the chamber, a mixed calculation model of interior ballistic two-phase flow combined with the particle element method and the two-fluid method was established. First, considering the different states of the combustion system in different periods, the particle element method was used to describe the initial charging state, while the two-fluid method was used to calculate the subsequent homogeneous flow. Next, the coupling and transformation of the two methods were realized by the boundary mapping. Finally, the mixed modeling method was validated by comparing the classic code results. Based on the novel approach, parameter distributions in the high-speed combustion chamber are obtained, and the particle movement and the development of the flow field in the chamber are described accurately. In the initial stage of ignition and flame-spreading, the flame front and heat transfer process appear completely. With the movement of the projectile, the flow field in the chamber changes drastically, and the particles gather toward the bottom of the projectile. When the propellant is burned out, the uniform distribution in the chamber is presented. The results indicate that the proposed method may be promising for a novel idea to obtain accurate parameter distributions in interior ballistic.