Simulation of Evaporated-Diffuse Combustion of a Single Micro Aluminum Droplet in Solid Rocket Motor

Metal additives such as aluminum powder can significantly affect the combustion and flow situation in the combustion chamber of solid rocket motors. This study aimed to investigate the evaporated-diffuse combustion process of aluminum particles in solid rocket motor chamber. We developed a quasi-steady two-dimensional evaporated-diffuse combustion model for a single aluminum particle. The evaporation rates of an aluminum droplet with spherical flame were calculated under different pressure. In addition, the effects of pressure and gas velocity on the combustion of gas and the micrometer-sized aluminum particle were investigated. The results show that the flame temperature increases with the rise of pressure. When the chamber pressure increases from 5MPa to 20MPa, the difference of maximum temperature in the flame zone reaches 610K; under the same chamber pressure (5 MPa), the deflection of the flame toward the flow direction is more significant at a higher gas flow rate. This indicates that the diffusion effect of combustion is more remarkable under high gas flow rate.