A Numerical and Experimental Study on the Effects of CO(2)on Laminar Diffusion Methane/Air Flames
A Numerical and Experimental Study on the Effects of CO(2)on Laminar Diffusion Methane/Air Flames
复制标题
CO(2)对层流扩散甲烷/空气火焰影响的数值和实验研究
DOI：
10.1115/1.4046228
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发表时间：
2020
影响因子：
3
通讯作者：
Levendis Yiannis A.
中科院分区：
文献类型：
--
作者：
Zhang Lei;Ren Xiaohan;Sun Rui;Levendis Yiannis A.
烟气再循环（FGR）是降低天然气等燃料燃烧过程中NOx排放的有效方法。氮、二氧化碳和水是烟气的主要成分。氮气是一种惰性气体，在FGR之前，水可以从流出物中冷凝出来。然而，回收的二氧化碳可以改变燃料的物理和化学燃烧特性。通过实验和数值模拟研究了CO2对甲烷/空气层流扩散火焰的影响。实验采用激光诱导荧光测量OH和CH分布在所产生的火焰中，在不同的CO2浓度。采用数值方法研究了反应机理，预测了温度场、组分浓度场以及NOx的生成。实验结果表明，随着CO2的加入，CH的荧光强度降低，OH的荧光强度增加。采用有向关系图法和灵敏度分析法对GRI-mech 3.0机构进行了简化。采用化学动力学分析软件包chemkin4.1中的扩散对流火焰模型，采用简化机理对甲烷燃烧进行了化学动力学分析，确定了主要组分间的主要反应。数值模拟结果表明，随着燃料中CO2含量的增加，CH浓度降低。这些CFD模拟使用的简化机制与实验数据一致。因此，还原机制，然后用于预测NO浓度。数值模拟结果表明，随着CO2在燃料中的量增加，CH的浓度降低，并作为一个结果，较低的量的NO预测。
Flue gas recirculation (FGR) is an effective method to reduce NOxemissions from the combustion of fuels, such as natural gas. Nitrogen, carbon dioxide, and water are the main components of flue gas. Nitrogen is an inert gas, and water can be condensed out of the effluent before FGR. However, recycled CO2can alter the physical and chemical combustion characteristics of a fuel. This research investigated the effects of CO2on CH4/air laminar diffusion flames, both experimentally and numerically. Experiments used laser-induced fluorescence to measure OH and CH distributions in the resulting flames, at different CO2concentrations. Numerical methods were used to investigate the reaction mechanism and predict temperature and species concentration fields, as well as the NOxformation. Experiments showed that the CH fluorescence intensities decreased with the addition of CO2,while the OH fluorescence intensities increased. Both the directed relation graph method and the sensitivity analysis method were used to reduce the GRI-mech 3.0 mechanism. The chemical kinetics of methane combustion were analyzed using the reduced mechanism with the diffusion opposed-flow flame model in thechemkin4.1 software package to determine the main reactions among the major species. Numerical simulations showed that as the amount of CO2in the fuel increased, the concentration of CH decreased. These CFD simulations using the reduced mechanism were in agreement with the experimental data. Thus, the reduced mechanism was then used to predict NO concentrations. Numerical simulations showed that as the amount of CO2in the fuel increased, the concentration of CH decreased, and, as a result, lower amounts of NO were predicted.