CO_2对乙烯层流预混火焰初生碳烟粒径演变的影响研究

Studies on the Nascent Soot Size Distribution in Laminar Premixed Ethylene Flame With CO_2 Addition

为了研究CO_2的添加对初生碳烟的影响,对添加了CO_2的乙烯层流预混滞止火焰进行了颗粒粒径分布检测,并采用修正的OPPDIF程序进行了火焰结构模拟。研究结果表明,CO_2的添加抑制了碳烟的生成,降低了成核速率和质量增长速率。CO_2与H原子的反应降低了重要气相组分H的浓度和增加了OH的浓度,而乙炔(C_2H_2)、炔丙基(C_3H_3)和苯(C_6H_6)的浓度也相应减小,并且反应温度有所降低,导致成核速率和质量增长速率均降低;而因为CO2的热容较大导致的温度降低对碳烟生成的影响较小。

The effect of CO2 addition on the nascent soot in laminar premixed ethylene flame was investigated by both experiments and simulations. The experimental results show that CO2 suppresses the formation of nascent soot by reducing the nucleation rate and mass growth rate; numerical simulations show the inhibition of soot formation by CO2 addition is mainly through chemical effect, increasing the concentration of OH and lowering the concentration of H, C2H2, C3H3, and C6H6, while the thermal effect only plays a minor role.