中文摘要：

为研究生物柴油对柴油机排放颗粒微观特性的影响,利用微孔均匀沉积式碰撞采集器（MOUDI）分析不同比例调合生物柴油颗粒物的粒径分布,利用扫描电镜（SEM）和透射电镜（TEM）观测微观形貌,根据计盒维数算法,计算颗粒物的分形维数。结果表明：调合生物柴油B20（在0#柴油中掺入20%的生物柴油）的粗态颗粒呈现分层堆积,原始粒子的粒径均大于45 nm,纯柴油（B0）的原始粒径为29 nm左右;所有颗粒物的质量浓度峰值均出现在0.18～0.32μm区间,发动机处于高负荷（75%和100%负荷）工况下,随着生物柴油掺混比的增加,积聚态和粗粒子态颗粒的质量浓度均逐渐下降,B20的积聚态颗粒质量下降至纯柴油的36.7%;两种计盒维数随生物柴油比例的增加而逐渐增加,说明颗粒物之间的重叠现象更明显,边界趋于不规则。

英文摘要：

Tests were carried out to research on microscopic characteristics of particles emitted from a diesel engine fueled with biodiesel. The effects of different proportions of biodiesel / diesel blends to particle size distribution were investigated by using micro-orifice uniform deposition impactor（ MOUDI）. Scanning electron microscope（ SEM） and transmission electron microscope（ TEM） were operated to observe particle microcosmic topographies. The fractal dimension of the particles emission was calculated according to the box-counting algorithm. The results indicate that coarse mode particles of B20（ 20% biodiesel is interfused into 0# diesel） are layered and mean diameter of primary particles is above 45 nm,and the diesel＇s（ B0） is approximately 29 nm. The peaks of particle mass concentration are all in the section of 0. 18 ～ 0. 32 μm. With increasing percentage of biodiesel,particle mass concentration of accumulation mode and coarse mode both decline and the mass ofB20＇s accumulation mode downs to 36. 7% of diesel＇s. Two kinds of box-counting dimensions increase gradually,which means primary particles become more closer and the boundaries change more irregularly.