压力对可燃极限非单调作用的机理分析  

Mechanism Analyses of Pressure Non-Monotonic Effect on Flammability Limits

作　　者：田雪沁[1] 陶志强[1] 张海[1] 

机构地区：[1]清华大学热能工程系,热科学与动力工程教育部重点实验室,北京100084

出　　处：《工程热物理学报》2011年第9期1601-1604,共4页Journal of Engineering Thermophysics

基　　金：国家自然基金资助项目(No.50576041)

摘　　要：采用CHEMKIN的PREMIX模块对非常压下贫燃侧的一维、层流CH_4/Air预混火焰进行数值模拟,分析了不同的压力下辐射引起的最高火焰温度损失、主要反应的敏感性系数和主要自由基摩尔分数的变化。结果表明,辐射热损失随着当量比的下降而加强,在非单调变化的拐点附近,热辐射损失对最高火焰温度的相对变化作用明显加强。随着压力增大,近极限火焰的主要链终止反应H+O_2+M=HO_2+M的敏感性呈现先增大后减小的非单调变化,并逐渐被HO_2+CH_3=OH+C_3O取代;引起以上变化的原因是,随着压力增大,HO_2对其它主要基团(OH、O、H)的相对浓度明显增大。1D, laminar premixed CH4/Air flames at elevated pressures were numerically studied to assess pressure effect on flammability limits, with attention primarily paid to maximum flame temperature loss caused by radiation, dominant chain branching and termination reactions and species profiles at different pressures. It was found that radiation heat loss effect increases with decreasing equivalence ratio, especially at the turning point showing the non-monotonic pressure effect. As pressure increases, sensitivity coefficient of main chain termination reaction H＋O2＋M=HO2＋M changes non-monotonously, firstly increases then decreases and this chain termination reaction is gradually substituted by reaction HO2＋CH3=OH＋CH3O. The main reason of such change is that the relative concentration of HO2 species becomes higher than that of other species as pressure increases.

关 键 词：预混火焰 压力 可燃极限 反应机理 

分 类 号：TK16[动力工程及工程热物理—热能工程]