Abstract <p>The gas-solid two-phase flow characteristics within the compression cavity of a solid carbon dioxide (CO₂) molding machine are investigated using numerical simulation. Initially, based on computational fluid dynamics (CFD), the effects of varying inlet inclination angles (0–60°) on the flow field structure within the cavity are analyzed, with a particular focus on examining the evolution of the velocity field, the pressure distribution, and the gas trajectory patterns. Subsequently, the discrete phase model (DPM) is applied to track the motion of snowflake-shaped dry ice particles, enabling a detailed examination of particle spatial distribution under flow interactions. Results indicate that an increase in the inlet inclination angle significantly enhances the main flow diffusion within the cavity, improving particle phase dispersion uniformity. However, further increases in the angle lead to a concomitant rise in the static pressure gradients, raising the risk of high-pressure injection events. An&#xa0;analysis of gas motion trajectories shows that, at the 45 and 60° inlet angles, the flow field exhibits a typical vortex-diffusion composite pattern. The primary gas flow forms stable spiral trajectories that enhance particle dispersion, while secondary flows effectively reduce particle deposition at the cavity bottom. In terms of the particle distribution, particles accumulate near the exhaust hole at the angle of 45°, increasing the cavitation risk, whereas at the angle of 60°, they concentrate primarily on the right side while maintaining optimal dispersion uniformity throughout the cavity. Comprehensive evaluation identifies the angle of 60° as the optimal inlet inclination for aerodynamic performance. This work provides critical theoretical foundation and engineering guidance for the aerodynamic optimization of solid CO₂ molding equipment.</p>