摘要
为研究正庚烷(n-C_(7)H_(16))在O_(2)/CO_(2)氛围下的燃烧特性,提出了基于CO_(2)与H·详细反应路径的C-H燃烧机理。通过密度泛函理论对CO_(2)与H·可能存在的反应路径进行了分析,根据定容燃烧弹实际尺寸建立了计算网格,利用C-H机理计算了正庚烷在不同氛围(空气、53%O_(2)/47%CO_(2)、61%O_(2)/39%CO_(2))下的燃烧过程;搭建了定容燃烧弹可视化实验平台,对正庚烷在不同氛围下的燃烧过程进行了测量;对CO_(2)的反应位点、CO_(2)+H·——→CO+·OH的反应能垒、火焰长度进行了分析。结果表明:C-H机理可以很好地预测正庚烷在O_(2)/CO_(2)氛围下的燃烧火焰长度,在50%O_(2)/50%CO_(2)氛围下的最大误差和平均误差分别为9.60%、2.42%;反应位点分析发现,CO_(2)氧原子的反应活性大于碳原子,氧端的平均局部离子化能和分子表面静电势分别为297.72 kcal/mol、-13.08 kcal/mol;H·与CO_(2)的碳原子和氧原子均可发生结合,反应能垒分别为26.71、11.07 kcal/mol。
In order to study the combustion characteristics of n-heptane under O_(2)/CO_(2)atmosphere,a C-H combustion mechanism based on the detailed reaction paths of CO_(2)and H·was proposed.The possible reaction paths of CO_(2)and H·were analyzed by using density functional theory,and the calculation grids were established according to the actual size of constant volume combustion chamber.The combustion processes of n-heptane under different atmospheres(air,53%O_(2)/47%CO_(2),61%O_(2)/39%CO_(2))were calculated through C-H mechanism.A constant volume incendiary bomb visualization experiment platform was built to measure the combustion process of n-heptane in different atmospheres.The reaction site of CO_(2),the reaction energy barrier of CO_(2)+H·→CO+·OH,and the flame length were analyzed.The results show that the C-H mechanism can well predict the combustion flame length of n-heptane under O_(2)/CO_(2)atmosphere,and the maximum error and the average error are 9.60%and 2.42%respectively under 50%O_(2)/50%CO_(2).The reactivity of oxygen atom of CO_(2)is higher than that of carbon atom,and the average local ionization energy and molecular surface electrostatic potential at the oxygen ends are 297.72 and-13.08 kcal/mol,respectively.H·can combine with carbon atom and oxygen atom of CO_(2),the reaction energy barrier are 26.71 and 11.07 kcal/mol,respectively.
作者
李晨曦
刘永峰
张璐
刘海峰
宋金瓯
何旭
LI Chenxi;LIU Yongfeng;ZHANG Lu;LIU Haifeng;SONG Jin’ou;HE Xu(Beijing Engineering Research Center of Monitoring for Construction Safety,Beijing University of Civil Engineering and Architecture,Beijing 102627,China;State Key Laboratory of Engines,Tianjin University,Tianjin 300072,China;School of Mechanical Engineering,Beijing Institute of Technology,Beijing 100081,China)
出处
《化工学报》
EI
CSCD
北大核心
2023年第5期2157-2169,共13页
CIESC Journal
基金
国家自然科学基金项目(51976007)
内燃机燃烧学国家重点实验室开放研究项目(K2023-04)
北京建筑大学研究生创新项目(PG2022129)。
关键词
二氧化碳
计算化学
计算流体力学
定容燃烧弹
反应位点
火焰长度
carbon dioxide
computational chemistry
computational fluid dynamics
constant volume combustion chamber
reaction site
flame length
