【摘要】 为探究船舶柴油机排放的NO_x中各成分的主要生成机理,基于6135Aca型柴油机,利用AVL Fire建立仿真模型,探究掺混生物柴油在不同负荷下对NO_x成分之间转换的影响机理。结果显示:柴油机排放的NO₂主要通过HO₂氧化NO生成,且高温和氧质量分数会影响NO₂的生成,其中高温会抑制NO₂的生成,氧质量分数增加会促进NO₂的生成;掺混生物柴油和增加负荷会使喷雾贯穿距增大,高温区域增加,从而抑制NO₂生成;掺混生物柴油使得燃烧室内氧含量增加,进而HO₂量增加促进NO₂生成;掺混比例较小时,NO₂主要受高温区域影响,当掺混到达一定比例时贯穿距不再增大,这时NO₂主要受氧含量影响。本文得到的NO₂生成机理,对降低NO_x中NO₂的排放比例有一定指导意义。更多还原

【Abstract】 To explore the main formation mechanism of components in marine diesel engine emissions NO_x, a simulation model based on 6135 Aca marine diesel engines is established by AVL Fire to explore the influence mechanism of blending biodiesel on the conversion of NO_x components under different loads. The results are the following: the diesel engine emission NO₂ is mainly produced by oxidation of NO by HO₂, and high temperature and oxygen mass fraction affect the formation of NO₂, in which high temperature inhibits the formation of NO₂, and the increase of oxygen mass fraction promotes the formation of NO₂; blending biodiesel and increasing load can make the spray penetration distance increase and the high temperature area increase so as to inhibit NO₂ formation; blending biodiesel can make oxygen content increase in combustion chamber, and thus HO₂ content increases so as to promote the formation of NO₂; when the blending ratio is smaller, NO₂ is mainly affected by the high temperature region; when the blending ratio reaches a certain level, the penetration distance does not increase any more, and NO₂ is mainly affected by oxygen content. The formation mechanism of NO₂ obtained has certain guiding significance for reducing the proportion of NO₂ in NO_x.更多还原