Wang Xin, Liu Fangjie, Zhang Qian, Li Xin, Liu Qinghua
College of Vehicle and Traffic Engineering, Henan University of Science and Technology, Luoyang 471023, China.
ACS Omega. 2022 Jul 11;7(28):24812-24823. doi: 10.1021/acsomega.2c02948. eCollection 2022 Jul 19.
Nitrogen dioxide (NO) is an active species of exhaust gas recirculation gas, and it has a significant impact on the autoignition and combustion processes of fuels. This study presented a comprehensive investigation of the effect of NO on the combustion characteristics of the -butanol/biodiesel dual fuel. Experiments were conducted on a single-cylinder engine with 0, 100, 200, and 400 v/v ppm NO addition at two fuel injection ratios. The findings of the experiments indicated that adding NO resulted in an earlier start of heat release and an increase in peak in-cylinder pressure as compared to experiments where no NO was added. The evolutions of -butanol, biodiesel, and OH radicals were evaluated using the computational fluid dynamics software coupled with the -butanol-biodiesel-NO mechanism. The results revealed that when 400 v/v ppm NO was added, the consumption of -butanol and biodiesel occurred earlier, and the formation of OH radicals was approximately an order of magnitude higher before the biodiesel was injected. Furthermore, reaction rate and flux analyses were performed to understand the effect of NO addition on the reaction process. When NO was added, 35% of the HO radicals reacted with NO which converted from NO via the reaction NO + HO ⇌ NO + OH, promoting the formation of OH radicals in the reaction system. The addition of NO can also enhance the consumption of CH radicals via the reaction CH + HO ⇌ CHO + OH.
二氧化氮（NO）是废气再循环气体的一种活性成分，它对燃料的自燃和燃烧过程有重大影响。本研究全面考察了NO对正丁醇/生物柴油双燃料燃烧特性的影响。在一台单缸发动机上进行了实验，在两种喷油比下分别添加0、100、200和400 v/v ppm的NO。实验结果表明，与未添加NO的实验相比，添加NO导致放热提前开始，缸内压力峰值增加。使用计算流体动力学软件结合正丁醇-生物柴油-NO反应机理评估了正丁醇、生物柴油和OH自由基的演变。结果显示，当添加400 v/v ppm的NO时，正丁醇和生物柴油的消耗提前发生，并且在注入生物柴油之前OH自由基的形成量大约高出一个数量级。此外，进行了反应速率和通量分析以了解添加NO对反应过程的影响。添加NO时，35%的HO自由基与通过反应NO + HO ⇌ NO + OH由NO转化而来的NO发生反应，促进了反应体系中OH自由基的形成。添加NO还可通过反应CH + HO ⇌ CHO + OH增强CH自由基的消耗。
