CIESC Journal ›› 2023, Vol. 74 ›› Issue (5): 2157-2169.DOI: 10.11949/0438-1157.20230018

• Energy and environmental engineering • Previous Articles     Next Articles

Quantum chemical analysis of n-heptane combustion mechanism under O2/CO2 atmosphere

Chenxi LI1(), Yongfeng LIU1(), Lu ZHANG1, Haifeng LIU2, Jin’ou SONG2, Xu HE3   

  1. 1.Beijing Engineering Research Center of Monitoring for Construction Safety, Beijing University of Civil Engineering and Architecture, Beijing 102627, China
    2.State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China
    3.School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
  • Received:2023-01-09 Revised:2023-05-05 Online:2023-06-29 Published:2023-05-05
  • Contact: Yongfeng LIU

O2/CO2氛围下正庚烷的燃烧机理研究

李晨曦1(), 刘永峰1(), 张璐1, 刘海峰2, 宋金瓯2, 何旭3   

  1. 1.北京建筑大学北京市建筑安全监测工程技术研究中心,北京 102627
    2.天津大学内燃机燃烧学国家重点实验室,天津 300072
    3.北京理工大学机械与车辆学院,北京 100081
  • 通讯作者: 刘永峰
  • 作者简介:李晨曦(1998—),男,硕士研究生,864173413@qq.com
  • 基金资助:
    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)

Abstract:

In order to study the combustion characteristics of n-heptane under O2/CO2 atmosphere, a C-H combustion mechanism based on the detailed reaction paths of CO2 and H· was proposed. The possible reaction paths of CO2 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%O2/47%CO2, 61%O2/39%CO2) 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 CO2, the reaction energy barrier of CO2+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 O2/CO2 atmosphere, and the maximum error and the average error are 9.60% and 2.42% respectively under 50%O2/50%CO2. The reactivity of oxygen atom of CO2 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 CO2, the reaction energy barrier are 26.71 and 11.07 kcal/mol, respectively.

Key words: carbon dioxide, computational chemistry, computational fluid dynamics, constant volume combustion chamber, reaction site, flame length

摘要:

为研究正庚烷(n-C7H16)在O2/CO2氛围下的燃烧特性,提出了基于CO2与H·详细反应路径的C-H燃烧机理。通过密度泛函理论对CO2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%O2/47%CO2、61%O2/39%CO2)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CO2的反应位点、CO2+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O2/CO2氛围下的燃烧火焰长度,在50%O2/50%CO2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,CO2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CO2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。

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

CLC Number: