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Study on the Formation Processes of Polycyclic Aromatic Hydrocarbon in a Fuel Spray Flame via Excitation Emission Matrix spectroscopy

激发发射矩阵光谱研究燃料喷雾火焰中多环芳烃的形成过程

基本信息

批准号：
14350103
负责人：
KOSAKA Hidenori
金额：
$ 8.32万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

项目摘要

In order to investigate the formation processes of the polycyclic aromatic hydrocarbons (PAHs) which are considered as soot precursors in a spray flame, Excitation Emission Matrix (EEM) spectroscopy which can be applied to the transient fuel spray at high temperature and high pressure was developed. The latter half of this study, the laser-induced fluorescence spectroscopy and 2-S imaging were applied to the spray flame in a rapid compression machine. The summary of the obtained results are followings(1)The stronger emission was observed in the incident side of the spray flame in the case of excitation by 226 nm wavelength than that in the case of 355 nm excitation. This indicates that the more kinds of species are excited and emit the fluorescence in the case of 266 nm excitation than that of 355 nm excitation.(2)In the case of 335 nm excitation, the LIF from formaldehyde formed in the low temperature oxidation process of fuel was detected before the hot ignition, this LIF from formaldehyde disappears rapidly and the LIF from PAHs are appears immediately after the hot ignition. In the case of 266 nm excitation, the LIF from formaldehyde was not detected before the hot ignition, but the LIF from impurities in fuel was observed. After the hot ignition, the strong LIF from PAHs appears which has the same spectrum as the case of 355 nm excitation.(3)In the both cases of 266 nm and 355 excitations, the LIF from PAHs can be observed in the central region of a spray flame between 35 mm and 45 mm from the nozzle orifice after the hot ignition. At the 55 mm from the nozzle orifice, the LII from soot particles is overlapped to the LIF from PAHs.

为了研究喷雾火焰中碳烟前体多环芳烃（PAHs）的形成过程，开发了适用于高温高压下瞬态燃油喷雾的激发发射矩阵（EEM）光谱技术。本研究的后半部分，将激光诱导荧光光谱和2-S成像技术应用于快速压缩机中的喷雾火焰。结果表明：（1）在226 nm波长激发下，喷雾火焰入射侧的发射强度明显高于355 nm波长激发下的发射强度;这表明，在266 nm激发的情况下比在355 nm激发的情况下，更多种类的物种被激发并发射荧光。(2)In 335 nm激发时，在热点火前检测到燃油低温氧化过程中形成的甲醛的激光诱导荧光，该甲醛的激光诱导荧光迅速消失，而在热点火后立即出现多环芳烃的激光诱导荧光。在266 nm激发的情况下，在热点火之前未检测到来自甲醛的LIF，但观察到来自燃料中的杂质的LIF。热点燃后，多环芳烃产生了与355 nm激发光相同的强激光诱导荧光。(3)In在266 nm和355 nm两种激发波长下，热点火后，在距喷孔35 ~ 45 mm的喷雾火焰中心区域都能观察到多环芳烃的激光诱导荧光。在距喷嘴口55 mm处，碳烟颗粒的LII与多环芳烃的LIF重叠。