论文部分内容阅读
为了研究二甲苯三种同分异构体的点火特性,获得该燃料燃烧反应重要自由基OH,CH和C2的变化信息,在化学激波管中利用反射激波点火,点火温度1224~1478K,点火压力0.18~0.21MPa,燃料当量比1.0,由单色仪光谱系统测得了二甲苯/空气的点火延迟时间,并用ICCD瞬态光谱探测系统测得了点火温度1440K时对二甲苯/空气燃烧的时间分辨瞬态发射光谱。实验结果表明:对二甲苯点火延时对温度的敏感程度最高,邻二甲苯和间二甲苯的点火延时对温度的敏感程度相近;在相同实验条件下,间二甲苯和对二甲苯的点火延迟时间比较接近,邻二甲苯的点火延迟时间最短。在对二甲苯燃烧反应中,OH,CH和C2自由基一旦出现很快达到其浓度峰值,但各个自由基的消失过程各不相同,CH和C2自由基存在的时间很短,且相对浓度变化趋势几乎完全一致,而OH自由基持续时间最长。
In order to study the ignition characteristics of the three isomers of xylene, the change information of OH, CH and C2, which are the important combustion reactions of the fuel, was obtained. In the chemical shock tube, the shock wave was ignited with the ignition temperature of 1224-1478K, Ignition pressure 0.18-0.21MPa and fuel equivalence ratio 1.0, the ignition delay time of xylene / air was measured by monochromator spectroscopy system, and the time of paraxylene / air combustion at 1440K with ignition temperature of 1440K was measured by ICCD transient spectroscopy system Resolved transient emission spectra. The experimental results show that the ignition delay of p-xylene is the most sensitive to temperature, and the ignition delay of o-xylene and m-xylene is close to the temperature. Under the same experimental conditions, the ignition of m-xylene and p- The delay time is relatively close, o-xylene ignition delay time is the shortest. In the para-xylene combustion reaction, OH, CH and C2 free radicals once reached their peak concentration, but the disappearance of each free radical process varies, CH and C2 free radicals exist for a short time, and the relative concentration changes The trend is almost exactly the same, while OH radicals last for the longest duration.