Li Jianhang, Li Chenyu, Liang Wenkai, Han Wenhu, Law Chung K
State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081, China.
Center for Combustion Energy, Tsinghua University, Beijing 100084, China.
J Phys Chem A. 2024 Oct 31;128(43):9510-9518. doi: 10.1021/acs.jpca.4c04778. Epub 2024 Oct 22.
In this work, effects of ozone (O) addition on ethylene-oxygen (CH-O) mixtures are computationally studied through the explosion limit profiles. The results show that the addition of minute quantities of ozone (with a mole fraction of 0.06% in the oxidizer) shifts the explosion limit of the CH-O-O mixtures to the low-temperature regime. Further increases in the ozone concentration gradually strengthen the negative temperature coefficient (NTC) behavior at the second limit. That is because the explosion limit is primarily controlled by the ethylene ozonolysis reaction, and both the sensitivity analysis and chemical reaction rate perturbation method reveal specific kinetic reasons. Furthermore, it is shown that with the increasing equivalence ratio, the explosion limit curve with minute ozone addition rotates counterclockwise around a crossover point, while the explosion limit curve becomes complicated and the NTC behavior appears on the second limit with larger quantities of ozone addition. Furthermore, the effects of dilutions of nitrogen (N), argon (Ar), carbon dioxide (CO), and water (HO) on the explosion limits are also studied. To elucidate the different wall elimination effects of different explosion limit regimes, the impacts of surface reactions of six radicals (H, O, OH, HO, HO, and HCO) have been examined and the dominant radicals are found to be H and HO. The H radicals significantly influence the first explosion limit, while the HO radicals impact the entire explosion limit.
在这项工作中，通过爆炸极限曲线对添加臭氧（O₃）对乙烯 - 氧气（C₂H₄ - O₂）混合物的影响进行了计算研究。结果表明，添加微量臭氧（在氧化剂中的摩尔分数为0.06%）会使C₂H₄ - O₂ - O₃混合物的爆炸极限向低温区域移动。臭氧浓度的进一步增加会逐渐增强第二极限处的负温度系数（NTC）行为。这是因为爆炸极限主要由乙烯臭氧化反应控制，敏感性分析和化学反应速率微扰方法都揭示了具体的动力学原因。此外，研究表明，随着当量比的增加，添加微量臭氧时的爆炸极限曲线会围绕一个交叉点逆时针旋转，而添加大量臭氧时，爆炸极限曲线会变得复杂，并且在第二极限处会出现NTC行为。此外，还研究了氮气（N₂）、氩气（Ar）、二氧化碳（CO₂）和水（H₂O）稀释对爆炸极限的影响。为了阐明不同爆炸极限区域的不同壁面消除效应，研究了六种自由基（H、O、OH、HO₂、H₂O₂和HCO）的表面反应影响，发现主要自由基是H和HO₂。H自由基对第一爆炸极限有显著影响，而HO₂自由基影响整个爆炸极限。
