Abstract: The purpose of this study is to investigate the characteristics of soot particles in C₂H₄/CO₂/O₂/N₂ combustion at equivalence ratio of 3.0-5.0. As the oxidant is switched from conventional air to CO₂/O₂/N₂ mixture, the key species C₂H₂, C₃H₃ responsible for formation of first aromatic ring, the typical aromatics and 4-ring aromatics total production rate all decrease greatly. In addition, with CO₂ mole fraction from 0.2 to 0.5 in the mixture, the soot particle number density, volume fraction, surface area density, which are three most important parameters to soot particle property, are suppressed obviously. Furthermore, the increasing content of CO₂ in the oxidizer influences mostly H, OH radical concentrations by two reactions: CO+OH=CO₂ H and H+O₂=O+OH, and the production rate of H, OH from the two reactions declined, which revealed that CO₂ in mixture has an inhibiting effect on soot particle generation.

Key words: O₂/CO₂ combustion, soot particle, polycyclic aromatic hydrocarbon, production rate

摘要： The purpose of this study is to investigate the characteristics of soot particles in C₂H₄/CO₂/O₂/N₂ combustion at equivalence ratio of 3.0-5.0. As the oxidant is switched from conventional air to CO₂/O₂/N₂ mixture, the key species C₂H₂, C₃H₃ responsible for formation of first aromatic ring, the typical aromatics and 4-ring aromatics total production rate all decrease greatly. In addition, with CO₂ mole fraction from 0.2 to 0.5 in the mixture, the soot particle number density, volume fraction, surface area density, which are three most important parameters to soot particle property, are suppressed obviously. Furthermore, the increasing content of CO₂ in the oxidizer influences mostly H, OH radical concentrations by two reactions: CO+OH=CO₂ H and H+O₂=O+OH, and the production rate of H, OH from the two reactions declined, which revealed that CO₂ in mixture has an inhibiting effect on soot particle generation.

关键词: O₂/CO₂ combustion, soot particle, polycyclic aromatic hydrocarbon, production rate