正庚烷“两阶段”自燃过程的动力学解析  

Kinetic Analysis of“Two-Stage”Auto-Ignition Process of n-Heptane

作　　者：朱珊珊[1] 高健 潘家营[2] ZHU Shan-Shan;GAO Jian;PAN Jia-Ying(Key Laboratory of Biofuels,Qingdao Institute of Bioenergy and Bioprocess Technology,Chinese Academy of Sciences,Qingdao 266101,China;State Key Laboratory of Engines,Tianjin University,Tianjin 300072,China)

机构地区：[1]中国科学院青岛生物能源与过程研究所,青岛266101 [2]天津大学内燃机燃烧学国家重点实验室,天津300072

出　　处：《工程热物理学报》2020年第11期2870-2875,共6页Journal of Engineering Thermophysics

基　　金：国家自然科学基金资助项目(No.51806230)。

摘　　要：本文利用平推流反应器模型,结合详细动力学机理,模拟了正庚烷/空气的预混气在不同反应器温度(TR)和当量比(Φ)条件下的两阶段自燃过程,重点考察了自燃第一阶段向第二阶段的过渡机制。基于计算结果,在TR-Φ平面上描绘出了自燃两阶段的过渡极限,并考察了压力和气壁换热的影响。研究发现,自燃第一阶段向第二阶段的过渡有热过渡和化学过渡两种过渡机制。化学过渡的核心机制是氢过氧化物分解放出的活跃自由基(OH等)促进了燃料分子脱氢、加氧和小分子氧化等放热反应的进行,从而促进了第一阶段向第二阶段的过渡。The two-stage auto-ignition processes of n-heptane/air mixtures were investigated numerically using the plug-flow reactor model considering detailed chemical kinetics under conditions with varied reactor temperature(T_R) and equivalence ratio(Φ).Special attention was given to the mechanism controlling the transition from the first stage to second stage ignition.Based on the numerical results,the first-to-second stage transition limits were depicted in the TR-Φ plane,and the influences of pressure and heat transfer between gas flow and reactor wall were discussed.This study identified two different transition modes,namely,the thermal transition mode and the chemical transition mode.The chemical transition mechanism was clarified:the active radicals(OH,etc.)released from decomposition of the accumulated hydroperoxides,significantly enhanced the exothermic reactions including the H-abstraction reactions of fuel molecule,the oxygen addition reactions of fuel molecule,and oxidation reactions of small molecules,thus promoting the first-to-second stage transition.

关 键 词：自燃 正庚烷 过渡极限 低温氧化 氢过氧化物 

分 类 号：TK401[动力工程及工程热物理—动力机械及工程]