不同压力下层流对冲C2 H4扩散火焰中碳烟生成的数值模拟研究

采用Chemkin中的对冲扩散火焰模型对C₂H₄对冲扩散火焰中碳烟颗粒的生成进行了数值模拟研究,重点关注不同压力下碳烟颗粒及部分气相小分子和前驱物的形成. 以0.1 atm为增量,探讨了1～5 atm内乙烯扩散火焰中多种中间产物和碳烟前驱物的浓度分布. 数值模拟结果表明,随着压力的不断增大,碳烟体积分数和碳烟数密度快速增加,H₂、CH₄等气相小分子的含量总体呈现下降趋势但变化不大,火焰面及气相小分子的生成区域变小. PAHs和C₂H₂含量的快速增加是通过HACA机理实现的,使得碳烟成核和生长速率加快,从而促进了碳烟数密度和体积分数的迅速增加.

Numerical Simulation of Soot Formation in Laminar C2H4Opposed-flow Diffusion Flames under Different Pressures

The opposed-flow diffusion flame model in Chemkin is used to simulate the formation of soot in C₂H₄ diffusion flames,focusing on the formation of soot particles and some gas phase small molecules and precursors under different pressures. The concentration distributions of various intermediates and soot precursors in C₂H₄ diffusion flames are investigated under pressure range of 1 to 5 atm in increments of 0.1 atm. The results show that with the increase of pressure,the volume fraction and number density of soot increase rapidly,the content of H₂,CH₄ and other small molecules decreases,and the formation area of small molecules in the flame surface and gas phase becomes smaller. The rapid increase of PAHs and C₂H₂ content is realized by HACA mechanism,which accelerates the nucleation and growth rate of soot,and promotes the rapid increase of soot number density and volume fraction.