Ignition and Combustion Characteristics of Micro‐Aluminum and Nano‐Aluminum Mixture

ABSTRACT While prior studies focus on individual aluminum powders, the combustion behavior of mixed nano‐ and micron‐sized aluminum particles remains unclear. This work investigates combustion characteristics of aluminum powders with different particle size combinations (29 µm, 15 µm, 1 µm, and 100 nm) under two conditions: a pure composition and a mass ratio of 72.2% micron‐sized particles to 27.8% nano‐sized particles. Additionally, the combustion characteristics of aluminum powders with best combustion performance particle size combinations were analyzed under six different oxidation environments (O₂, N₂, and CO₂) and various packing densities. The results indicate that the mixed aluminum powder with a 72.2% mass ratio of 29 µm particles and 27.8% mass ratio of 100 nm particles exhibits the best overall combustion performance. Among the six oxidizing atmospheres, the mixed aluminum powder demonstrated the highest combustion performance in a pure oxygen environment. The combustion performance of mixed aluminum powder is most effective at a density of 2.9 g/cm 3 . The combustion performance of aluminum powder is significantly enhanced when nano‐ and micron‐sized aluminum powders are mixed. This improvement is attributed to the synergistic benefits of combining the two sizes, where nano‐sized aluminum, with its high specific surface area, facilitates rapid oxidation kinetics and intense combustion, while also generating more gaseous products that boost thrust. Conversely, micron‐sized aluminum provides effective heat conduction and stability, acting as a thermal reservoir that prolongs combustion duration and mitigates agglomeration. This system enables quick ignition and a balanced release of energy, optimizing both reaction efficiency and thrust stability.