Analysis on First-stage Ignition of n-Heptane at Low Temperatures with a Lumped Skeletal Mechanism  

作　　者：XIAO Jiayu WANG Jingbo WANG Fan LI Xiangyuan 

机构地区：[1]College of Chemical Engineering,Sichuan University,Chengdu,610065,P.R.China [2]Engineering Research Center of Combustion and Cooling for Aerospace Power,Ministry of Education,Sichuan University,Chengdu,610065,P.R.China [3]Institute of Atomic and Molecular Physics,Sichuan University,Chengdu,610065,P.R.China

出　　处：《Chemical Research in Chinese Universities》2022年第6期1482-1491,共10页高等学校化学研究（英文版）

基　　金：supported by the National Science and Technology Major Project of China (No.2017-I-0004-0004).

摘　　要：Two-stage ignition exists in the low-temperature combustion process of n-heptane and the first-stage ignition also shows a negative temperature coefficient(NTC) phenomenon. To study key reactions and understand chemical principles affecting the first-stage ignition of n-heptane, a lumped skeletal mechanism with 62 species is obtained based on the detailed NUIGMech1.0 mechanism using the directed relation graph method assisted by sensitivity analysis and isomer lumping. The lumped mechanism shows good performance on ignition delay time under wide conditions. The study revealed that the temperature after the first-stage ignition is higher and a larger amount of fuel is consumed at lower initial temperatures. The temperature at the first-stage ignition is relatively insensitive to the initial temperature. Further sensitivity analysis and reaction path analysis carried out based on the lumped mechanism show that the decomposition of RO_(2) to produce alkene and HO_(2) is the most important reaction to inhibit the first-stage ignitions. The chain branching explosion closely related to the first-stage ignition will be terminated when the rate constant for the RO_(2) decomposition is larger than that of the isomerization of RO_(2) to produce QOOH. The NTC behavior as well as other characteristics of the first-stage ignition can be rationalized from the competition between these two reactions.

关 键 词：Reduced mechanism Lumping of isomer Low-temperature reaction First-stage ignition Negative temperature coefficient(NTC) phenomenon 

分 类 号：O6[理学—化学]