正庚烷-甲醇二元燃料着火的23步反应模型  

A Skeletal Chemical Kinetic Model Containing 23 Reactions for the Ignition of N-Heptane/Methanol Dual Fuel

作　　者：许汉君[1] 姚春德[1] 徐广兰[1] 

机构地区：[1]天津大学内燃机燃烧学国家重点实验室,天津300072

出　　处：《内燃机学报》2011年第5期391-397,共7页Transactions of Csice

基　　金：国家自然科学基金资助项目(50876075)

摘　　要：试验发现,与甲醇混合或在甲醇氛围中,柴油、正庚烷的着火受到一定的抑制.为了揭示其机理,采用零维模型对甲醇影响正庚烷着火的化学反应进行了分析.结果表明,在温度低于1 000 K时,由于甲醇的存在,OH大量转化为H2O2,而此时H2O2分解的活化能较高,尚不能大规模参与反应,从而降低了系统的活性.但温度超过1 000 K时,H2O2分解为OH的势垒被打破,甲醇的抑制作用即消失.根据以上分析结果,创建了用于预测着火的骨架反应模型,共包含23步反应、23种物质,计算结果表明,该模型对各个当量比和掺混比的燃料两阶段着火时刻和重要物质变化规律有较好地预测.Previous experimental studies showed that the ignition delay of diesel and/or n-heptane mixed with methanol, or injected in the methanol/air atmosphere would increase. To clarify this mechanism, a zero-dimensional model was used to analyze the influence of methanol on the ignition of n-heptane. Results show that OH is converted to H2O below 1 000 K due to the existence of methanol, those H2O2 are frozen due to its high decomposition activation energy. Thus, the activity of the whole reaction system is deceased. However, the barrier of the decomposition of H：O： is broken down when temperature rises above 1 000 K, and methanol suppression effect will disappear. Based on analysis above, a skeletal kinetic model was proposed to predict the ignition delay of methanol and n-heptane mixture. The model includes 23 reactions and 23 species. Simulation result shows two-stage heat release and the concentrations of some main species in low temperature oxidation can be well predicted by this model at different equivalence ratios and mixing ratios.

关 键 词：甲醇 正庚烷 柴油 着火模型 骨架模型 

分 类 号：TK421[动力工程及工程热物理—动力机械及工程]