Study on multi-dimensional gas-particles reaction flow characteristics of reduced-load modular charge under an extreme condition

The central focus of this research lies in studying the complicated evolution mechanism of the in-bore gas-particles flow field and the influence of flow variation on the thermal transport properties of the reduced-load modular charges chamber under high-pressure conditions. To analyze the flow field structure—particularly vortex dynamics and spatiotemporal pressure characteristics—before and after projectile displacement, we develop a coupled multiphase flow model integrating propellant combustion. The model combines an improved Euler–Lagrange approach with the Euler–Euler method. Comparisons of chamber-pressure are done with experimental studies by establishing a combustion–propulsion experiment platform, and a good agreement is reached within 8.03% uncertainty. Furthermore, the combustion gas flows into the modular cartridges as well as the free volume in the bore radially and axially, as the primer jet ignites the ignition charge, generating vortices near the boundary regions inside the modular cartridges and the projectile base. The bore pressure primarily exhibits an axial gradient after the consecutive breakage of the two module cartridges, causing the gas-particles biphasic flow to undergo periodic reciprocating motion between the breech and the projectile base with the pressure difference fluctuating between −4.73 and 4.62 MPa. Also, the chamber vortices show a morphological evolution process of first split and then merger at the chamber boundaries and the convergence boundaries of multiple airflow streams. Concurrently, under the competing mechanisms of increasing propellant gas mass and expanding volume behind the moving projectile, the bore pressure first rises and then declines with the strong periodic pressure oscillation in the chamber. The research results have certain reference value for exploring the three-dimensional flow field characteristics of modular charged artillery under small charge.