进气初始条件对柴油机低温燃烧及PAHs排放特性的影响

Effects of inlet initial conditions on low temperature combustion process and PAHs emission characteristics of diesel engines

中文关键词: 柴油机  化学动力学模型  低温燃烧  排放特性

英文关键词: diesel engines  chemical dynamics model  low temperature combustion  emission characteristics

中文摘要:

      应用三维CFD模型耦合化学动力学模型的方法，研究了进气初始条件对柴油机低温燃烧及多环芳香烃（PAHs）排放特性的影响规律。结果表明：进气温度降低，滞燃期延长，同时进气密度增大，使柴油机的循环进气量增多，空燃比升高，燃油在缸内燃烧氧化更充分，在较低的进气温度工况时缸内生成PAHs各组分相对较低；进气压力的升高，PAHs各组分的生成时刻提前，并且PAHs各组分的含量依次减少。燃烧起始阶段，苯（C6H6）主要分布在燃烧室凹坑附近。在燃烧中期与后期，主要分布在凹坑壁面附近。

英文摘要:

      Based on three-dimensional CFD model coupled with reduced chemical dynamics model method, this paper studies the effects of inlet initial conditions on low temperature combustion process and PAHs emission characteristics of diesel engines. The results indicate that the ignition delay time is longer when intake temperature was reduced, while the air input and air-fuel ratio increase when intake density increasing resulting in lower generation of PAHs component. With the increasing of intake pressure, the generation time of PAHs components was earlier and the content of PAHs components was reduced.Benzene is mainly distributed near the combustion chamber pit in burning combustion stage and mainly distributed near the pit wall in middle and late combustion stage.