Al/Bi₂O₃复合材料反应燃烧特性的数值分析

Numerical Simulation of Combustion Char-acteristics of Nanothermite Al/Bi₂O₃

为研究Al/Bi2O3纳米铝热剂的燃烧特性,基于固体传热、燃烧波和化学动力学相关理论,建立了一维燃烧波传播模型,采用COMSOL Multiphysics软件,数值分析了Al/Bi2O3化学燃烧反应过程中的燃烧特性。结果表明,Al/Bi2O3在反应过程中经历了点火前升温阶段、燃烧波传播阶段和局部热力学平衡阶段三个燃烧阶段。当Al和Bi2O3的摩尔配比为理论计量比2时,Al/Bi2O3复合物具有最好的燃烧性能,平衡温度可达4217 K,最大反应速率和燃烧波传播速度分别为1.36215;1071和671.6 m/s。随着反应物粒径和活化能的减小,Al/Bi2O3的平衡温度逐渐减小,最大反应速率和燃烧波传播速度却逐渐增大。而反应点火延迟时间取决于反应物的活化能大小。

To study combustion characteristics of nanothermite Al/Bi2O3, a one-dimensional combustion model was established based on solid heat-transfer, combustion theory and chemical kinetics. By using COMSOL Multiphysics, combustion characteristics of nanothermite Al/Bi2O3 were simulated. The results show that there are three steps in the reaction, including heating up before combustion, diffusion of combustion and local thermodynamic equilibrium. The Al/Bi2O3 with stoichiometric ratio (2?1) has the best combustion characteristics. The highest equilibrium temperature, reaction rate and combustion velocity are 4217 K, 1.36 ×107 s?1 and 671.6 m/s respectively. With the decrease of particle size and activation energy, equilibrium temperature decreased, but the reaction rate and velocity of combustion increased. And the reaction delay time depended on the activation energy.