基于多步反应机理的增厚层流预混火焰结构分析  

Thicked Laminar Premixed Flame Structure Analysis Based on Multistep Reaction Mechanism

作　　者：郭实龙 卫旭涛 张猛[1] 王金华[1] 黄佐华[1] GUO Shi-Long;WEI Xu-Tao;ZHANG Meng;WANG Jin-Hua;HUANG Zuo-Hua(State Key Laboratory of Multiphase Flow in Power Engineering,Xi＇an Jiaotong University,Xi＇an 710049,China)

机构地区：[1]西安交通大学动力工程多相流国家重点实验室,西安710049

出　　处：《工程热物理学报》2018年第11期2573-2577,共5页Journal of Engineering Thermophysics

基　　金：国家自然科学基金(No.51376004;No.91441203)

摘　　要：增厚火焰模型是燃烧计算中的有效方法之一,然而增厚火焰模型耦合多步机理时增厚系数会对火焰结构产生重要影响。本文采用基于OpenFOAM开发的增厚火焰求解器,分别计算了不同增厚系数下的增厚和动态增厚三维自由传播平面火焰。对比火焰结构发现,相比于原始火焰结构,增厚和动态增厚火焰面内部的自由基浓度并没有发生显著变化。增厚火焰已燃气体的温度和CO_2浓度均降低,同时CO和OH基浓度升高,动态增厚火焰中没有这一现象。对比分析认为,增厚模型导致燃烧产物温度降低是物理化学作用的共同结果。动态增厚火焰面的内部结构由于增厚系数的动态变化而发生了改变,但这一改变并不影响火焰面的几何结构和燃烧的最终状态。动态增厚模型耦合多步反应机理可以对层流火焰速度、已燃气体组分和温度进行有效预测。Thickened flame （TF） model is one of the effective methods to simulate combustion phenomenon. Theoretically, it could be extended to multi-step chemical reaction mechanism. In this work, the freely propagating planer flames with various thickening factor are simulated using TF model. The solver is developed based on OpenFOAM. The results shown that TF model coupled with multi-step mechanism will underestimate burnt gas temperature. Meanwhile, some post-flame species （CO, OH） concentration are overestimated, which means the decrease in burnt gas temperature is mainly caused by enhanced species diffusion. Dynamic thickened flame （DTF） model coupled with multi-step mechanism performs well for predicting species concentration and combustion state. So it is not recommended to use TF model coupled with a multi-step chemical reaction mechanism.

关 键 词：增厚模型 多步机理 层流火焰结构 

分 类 号：TK121[动力工程及工程热物理—工程热物理]