CH4-O2-N2预混气体爆炸二维数值模拟

 利用CFD软件，基于ISAT算法和简化的甲烷氧化基元反应模型，建立了CH₄-O₂-N₂预混气体的二维湍流爆炸模型。数值计算结果表明，该模型较好地模拟了CH₄-O₂-N₂预混气体在高温气团作用下的点火、燃烧和爆炸过程。计算中，考察了高温点火气团的初始温度和混合气体初始组分对CH₄-O₂-N₂预混气体燃烧和爆炸过程的影响。结果表明：高温气团的初始温度对CH₄-O₂-N₂预混气体的点火延迟时间和燃烧初始阶段有重要影响，但对CJ爆燃没有影响；惰性气体N₂的加入，降低了混合气体的反应活性，导致点火延迟时间增大，燃烧反应速度、爆炸超压和重要自由基浓度都随之减小。相同条件下爆炸超压峰值的计算结果与实验测量结果符合较好。

Two-Dimensional Numerical Simulation of Explosion for Premixed CH4-O2-N2 Mixture

Based on the reduced methane oxidized element reaction model, CFD software and ISAT algorithm were used to establish a two-dimensional turbulent explosion model for premixed CH₄-O₂-N₂ mixture. Computational results show that the process of ignition, combustion and explosion of the premixed CH₄-O₂-N₂ mixture can be simulated well by the model. The influence of the initial temperature of the high temperature core and the component of mixture on combustion and explosion were considered in the numerical computations. Simulation results indicate that the initial temperature of the high temperature core has an important effect on the ignition delay time and the early combustion phase of the premixed CH₄-O₂-N₂ mixture, but it hardly affects the CJ deflagration phase. The reaction activity of the premixed mixture is reduced by adding N₂, which results in the increase of ignition delay time and the decrease of deflagration reaction speed, explosion overpressure and free radical concentration. The computational results of explosion overpressure are in good agreement with experimental results on the same conditions.