关键词: 铝镁合金颗粒, 着火过程, 氧化性气体, 着火时间, 表面多相化学反应

Abstract:

Al-Mg alloy particles， characterized by short ignition delay times and rapid combustion rates， serve as critical metal additives in solid propellants. An experimental system for investigating the ignition characteristics of metal particles in high-temperature gas environments was employed to measure the ignition times of aluminum-magnesium alloy particles exposed to high-temperature gas mixtures composed of O₂，H₂O， and CO₂. A simulation method for the ignition process of aluminum-magnesium alloy particles was developed， incorporating the combined effects of convection heat transfer， radiation heat transfer， and Heterogeneous Surface Reaction （HSR）. The computational results for particle ignition times were validated， showing a prediction error within 15%. The ignition process of 100 μm spherical atomized Al-Mg alloy particle with 90wt% Al content in oxygen concentration of 30.4% condition was simulated. Results indicate that the heat contributions from convection heat transfer， radiation heat transfer， and HSR heat release maintained a ratio of approximately 2∶2∶1. Specifically， exothermic reactions involving oxygen accounted for 59.44% of the total heat release， while those involving magnesium contributed 25.82%. The ignition time of aluminum-magnesium alloy particles is significantly influenced by the gas flow velocity and temperature of the high-temperature environment. The former primarily affects ignition time by altering convection heat transfer rates， whereas the latter primarily impacts ignition time through variations in radiation heat transfer rates.

Key words: Al-Mg alloy particle, ignition process, oxidizing gas, ignition time, heterogeneous surface reaction