Transmission electron microscopy of soot directly sampled at different axial locations in diesel spray flame
Transmission electron microscopy of soot directly sampled at different axial locations in diesel spray flame
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DOI：
10.1299/transjsme.15-00348
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
K. Kondo;Teruo Yamaguchi;Hiroki Nishigai;T. Aizawa
中科院分区：
文献类型：
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作者：
K. Kondo;Teruo Yamaguchi;Hiroki Nishigai;T. Aizawa
为了进一步减少柴油车的颗粒物排放，了解火焰中碳烟的形成和氧化过程是非常重要的。为了澄清的过程中，直接采样在喷雾火焰中的不同位置（40毫米至90毫米，从喷嘴尖端）的碳烟的形态进行了研究，使用透射电子显微镜（TEM）。柴油喷雾火焰是在一个定容燃烧室中，在类似柴油的条件下（2.5 MPa和940 K）。在上游区域（40 ~ 50 mm），烟粒的浓度、直径和回转半径先增大，在中游区域（60 ~ 70 mm）附近出现一个峰值，然后在下游区域（80 ~ 90 mm）减小，这分别对应于烟粒在喷雾火焰中的形成、浓度峰值和氧化。烟粒聚集体的分形维数也进行了分析，几乎是恒定的，在不同的轴向位置在喷雾火焰中的值约为1.73，这表明在火焰中的烟粒聚集体的主要增长过程是集群集群聚集在扩散限制制度。
For further reduction of particulate emission from a diesel vehicle, it is fundamentally important to understand in-flame soot formation and oxidation processes. In order to clarify the processes, the morphology of soot directly sampled at different locations in the spray flame (40 mm to 90 mm from the injector nozzle tip) were investigated using a transmission electron microscope (TEM). The diesel spray flame was achieved in a constant volume combustion chamber under diesel-like conditions (2.5 MPa and 940 K). The concentration, diameter of primary particles and the radius of gyration of soot aggregates increased in the upstream region (40 to 50 mm), exhibited a peak around the mid-stream region (60 to 70 mm), and then decreased in the downstream region (80 to 90 mm), which corresponds to formation, peak concentration and oxidation of soot particles in the spray flame, respectively. The fractal dimension of soot aggregates was also analyzed and was almost constant, with a value of approximately 1.73 over different axial locations in the spray flame, which suggests that the dominant growth process of in-flame soot aggregate is cluster-cluster aggregation in diffusion limited regime.