CO_2添加对碳烟生成及其尺寸分布的影响

Influence of CO_2 Addition on Soot Formation and Particle Size Distribution

基于颗粒群演化的模拟理论方法,构建了一维稳态层流预混火焰中碳烟颗粒动力学演化过程的数学模型.通过耦合含有生成芘分子(A4)的详细化学反应机理,并采用蒙特卡洛(Monte Carlo)随机算法求解颗粒群平衡方程获得碳烟颗粒动力学演变尺寸分布信息.在此基础上,详细分析了层流预混火焰中二氧化碳添加对碳烟颗粒物尺寸分布的影响.结果表明:添加二氧化碳降低了碳烟颗粒成核速率,使得小粒径碳烟颗粒数密度减小;同时,添加二氧化碳减弱了碳烟颗粒表面生长速率,以及提高了OH和O2浓度而加速了碳烟的氧化反应,使得大粒径碳烟颗粒数密度降低.CO2添加对碳烟颗粒生成起到了一定抑制作用.

Based on the theoretical approach of particle population balance modeling,the evolution of soot particle dynamics model was built in the laminar one-dimensional premixed flames.The soot particle size distribution was obtained by coupling with the detailed chemical kinetic mechanism including the pyrene molecules generation.Monte Carlo method was used to solve the population balance equation.Effect of carbon dioxide addition on soot formation in the laminar premixed flames was investigated.Results showed that addition of carbon dioxide decreases the particles nucleation rate,decreasing the density number of small size particle.Moreover,carbon dioxide addition reduces the particles growth rate.Particles oxidation is accelerated by increasing the oxygen and hydroxide radical concentration,decreasing the density number of large size particle.Carbon dioxide addition inhibits the soot formation.