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利用反射激波方法开展了煤油/空气混合气在温度为1445~1650K,压力为0.1MPa,当量比为1.0条件下的着火滞燃期研究.采用拉瓦尔喷管雾化装置雾化煤油形成气溶胶,入射激波促使煤油气溶胶快速蒸发和扩散,反射激波诱导煤油/空气混合气着火.利用ICCD冻结煤油/空气混合气着火流场,进行着火特性的可视化分析.初始温度增加,煤油/空气混合气着火变强,温度小于1515K时,在整个观察范围内,火焰呈现连续但不规律形态.温度大于1560K时,火焰呈平面但不连续形态.实验结果表明:煤油/空气混合气的着火滞燃期随初始温度的增加而缩短,在整个研究范围内,煤油/空气混合气的总活化能未发生变化.实验结果与文献数据吻合很好.本文提出了新的三组分(10%甲苯/10%乙苯/80%正葵烷)煤油替代品,并使用Honnet机理进行着火滞燃期的数值模拟,在整个研究范围内,计算值与实验值有较好的吻合性.敏感性分析表明,反应H+O2<=>OH+O对着火滞燃期的敏感性系数最高,随着温度增加,敏感性系数随之增加.CH3的消耗反应对整个链分支反应起促进作用,正葵烷的脱氢反应对整个链反应起抑制作用.基元反应速率(ROP)和瞬态放热率分析得出:H+O2<=>OH+O和O+H2<=>OH+H是OH生成的主要基元反应,同时也是着火过程中主要吸热反应,链终止反应R3是着火过程中主要的放热反应.火焰结构分析表明CO和H2O出现在主燃之前,并导致初始压力在显著着火之前略有升高.
The study of ignition and ignition retardation of kerosene / air mixture at 1445 ~ 1650K, 0.1 MPa and equivalent ratio of 1.0 was carried out by means of reflection shock method. The Laval nozzle atomization device was used to atomize kerosene to form gas Sol and incident shock wave to promote rapid evaporation and diffusion of kerosene aerosol.The reflected shock wave induced the kerosene / air mixture to ignite.Using ICCD to freeze the kerosene / air mixture flow, the ignition characteristics were visualized.With the initial temperature increasing, kerosene / The air mixture became stronger and the flame became stronger.When the temperature was less than 1515K, the flame showed a continuous but irregular shape in the whole observation range.When the temperature was higher than 1560K, the flame was flat but discontinuous.The experimental results showed that the flame of kerosene / air mixture The ignition delay period shortened with the increase of initial temperature, and the total activation energy of kerosene / air mixture did not change throughout the study.The experimental results are in good agreement with the literature data.The new three-component (10% Toluene / 10% ethylbenzene / 80% n-heptane) kerosene substitutes, and using Honnet mechanism to simulate the ignition delay of ignition, the calculated values are in good agreement with the experimental values Sensitivity analysis showed that the sensitivity coefficient of reaction H + O2 <=> OH + O to ignition delay was the highest, with the increase of temperature, the sensitivity coefficient increased subsequently.The depletion of CH3 accelerated the whole chain reaction , The dehydrogenation reaction of n-pentane inhibited the whole chain reaction.The elementary reaction rate (ROP) and transient heat release rate analysis showed that: H + O2 <=> OH + O and O + H2 <=> OH + H is the main elementary reaction generated by OH and also the main endothermic reaction during ignition, and the chain termination reaction R3 is the main exothermic reaction during the ignition.Flame structure analysis shows that CO and H2O appear before the main combustion and Resulting in a slight increase in initial pressure before significant ignition.