Study on NOx Formation Mechanism in Counterflow Flames

逆流火焰中NOx形成机理研究

基本信息

批准号：
07455094
负责人：
TAKENO Tadao
金额：
$ 4.48万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07455094/
关键词：
NOx nitrogen oxides counterflow flames thermal mechanism Fenimore mechanism laser-induced fluorescence HCN recycle route NOx レーザ誘起蛍光法 Thermal機構

项目摘要

In this work, methane-air counterflow diffusion flame, counterflow double flame and one-dimensional premixed flame were simulated numerically with detailed chemical kinetics, and the NO formation processes were investigated by drawing quantitative reaction path diagram based on the reaction rates per unit flame area. As a result, it was found that the dominant NO formation mechanism among the thermal mechanism, Fenimore mechanism and HCN recycle route differs with the flame types or conditions such as equivalence ratio or velocity gradient. In addition, the dominant elementary reaction in NO formation was investigated by means of the sensitivity analysis of the emission index of NO,and it was found that the initiation reactions of the respective mechanisms descrived above are generally dominant and the relative importance of them differs with the flame types or conditions. Furthermore, the exisymmetric two-dimensional numarical calculation was also conducted for the coflow diffusion flame, and a good agreement was obtained between the flame structure of any cross section normal to the flame surface of the coflow flame and the structure of the counterflow diffusion flame of the same representative diffusion time.Experimentally, No concentlation distribution was measured by PLIF method, in order to verify the chemical kinetics used in the calculations. Here, the object was changed from the counterflow flame to the axisymmetric coflow flame, because the beam path in the flame zone of the counterflow flame is so long that the absorption is large, which results in a significant inaccuracy of the measurement. Comparing the fluorescence distribution obtained in the experiment with the NO concentration of the numerical result, a good agreement was obtained around the flame surface and the downstream, while the difference is somewhat large in the fuel side of the flame. The cause of the latter difference must be clarified before verifying each elementary reaction in detail.

在这项工作中，用详细的化学动力学模拟了甲烷 - 空气反流扩散火焰，逆流双火和一维预定的火焰，并根据单位火焰面积的反应速率绘制定量反应路径图，研究了无构造过程。结果，发现热机理，fenimore机理和HCN回收路线之间的主要没有形成机理，而火焰类型或条件（例如等效率或速度梯度）有所不同。此外，通过对NO的发射指数的敏感性分析，研究了NO形成的主要基本反应，并发现上述所描述的各个机制的起始反应通常是主要的，并且它们的相对重要性与火焰类型或条件不同。此外，还为Coflow扩散火焰进行了外部二维数值计算，并且在任何横截面的火焰结构之间获得了良好的一致性，与Coflow Flame的火焰表面的火焰结构正常，与相同代表性扩散时间的逆流变化的结构相同。用于计算。在这里，物体从逆流火焰更改为轴对称的Coflow火焰，因为逆流火焰火焰区域中的梁路径太长，以至于吸收很大，这会导致测量的严重不准确。将实验中获得的荧光分布与数值结果的无浓度进行比较，在火焰表面和下游获得了良好的一致性，而在火焰的燃料侧，差异有些较大。在详细验证每个基本反应之前，必须阐明后一个差异的原因。