Dilution, Thermal, and Chemical Effects of Carbon Dioxide on the Exergy Destruction in n-Heptane and Iso-octane Autoignition Processes: A Numerical Study
Dilution, Thermal, and Chemical Effects of Carbon Dioxide on the Exergy Destruction in n-Heptane and Iso-octane Autoignition Processes: A Numerical Study
复制标题
DOI：
10.1021/acs.energyfuels.7b04018
复制
发表时间：
2018-04
期刊：
影响因子：
5.3
通讯作者：
Jiabo Zhang;Zhen Huang;K. Min;D. Han
中科院分区：
文献类型：
--
作者：
Jiabo Zhang;Zhen Huang;K. Min;D. Han
基于热力学第二定律，对添加CO2的绝热定容系统中正庚烷和异辛烷自燃过程进行了数值分析。在低温区和高温区的初始温度下，对正庚烷和异辛烷的自燃过程进行了详细的化学机理模拟。在自燃过程的不同反应阶段，即燃料串联反应阶段、燃料碎片反应阶段、H_2O_2循环反应阶段和H_2-O_2反应阶段，通过数值分离CO2添加的稀释效应、热效应和化学效应来评价各反应阶段对(火用)破坏的影响。结果表明，异辛烷自燃燃料串联反应阶段的(火用)损失低于正庚烷，但CO2单独作用对两种燃料的(火用)破坏作用相同。CO_2的稀释效应降低了火用损失。
A numerical analysis based on the second-law thermodynamics was conducted for the n-heptane and iso-octane autoignition processes in an adiabatic constant-volume system with CO2 addition. Detailed chemical mechanisms of n-heptane and iso-octane were used in the autoignition processes simulation at the initial temperatures located in the low-temperature region and the high-temperature region. The dilution, thermal, and chemical effects of the CO2 addition were numerically isolated to evaluate each individual effect on the exergy destruction in different reaction stages of the autoignition processes, namely, the fuel-series reaction stage, the fuel-fragment reaction stage, the H2O2 loop reaction stage, and the H2-O2 reaction stage. It was observed that the exergy loss in the fuel-series reaction stage of iso-octane autoignition was lower than that of n-heptane, but the individual effect of CO2 played the same role in the exergy destruction for both fuels. The dilution effect of CO2 reduced the exergy loss i...