Flow Characteristics of Composite Droplets in the Combustion State Impacting a Wall

During the operation of a solid rocket motor (SRM), the behavior of condensing particles impacting the wall significantly influences the internal structure and performance of the SRM. Especially under overload conditions, the condensate particles form local high-concentration particle flows due to inertia forces, continually eroding the surface of the insulation layer and nozzle, which seriously affects the SRM's operational safety. In this paper, the impact behavior of condensed particles in the SRM environment is systematically studied. First, the geometric model of alumina/aluminum composite droplets is established through theoretical analysis, and the contact angle of aluminum droplets in a liquid alumina environment is obtained for the first time. Second, based on the volume of fluid (VOF) method and adaptive mesh method, an innovative numerical method is proposed to simulate the collision process of composite droplets. Finally, the dynamic behavior and evolution mechanism of alumina/aluminum composite droplets impacting the wall are deeply analyzed, revealing the flow characteristics of burning aluminum droplets impacting the wall in different incident states. This research provides a theoretical basis for the analysis of multiphase flow in the SRM combustion chamber.