甲醇—异辛烷混合燃料滞燃期研究

Study on Ignition Delay Period of Methanol-isooctane Blended Fuel

对Curran的异辛烷详细化学动力学机理和Li的甲醇化学动力学机理进行了甲醇着火滞燃期特性对比研究,发现Curran异辛烷机理基本能反映甲醇的自燃着火过程。基于此,利用Curran异辛烷机理对甲醇—异辛烷混合燃料在初始温度为600 K^1 600 K、压力为1.0 MPa^4.0 MPa、当量比为0.3~1.5范围内的着火滞燃期特性进行了计算研究,分析燃料特性和初始条件对混合燃料滞燃期的影响。结果表明,初始温度对甲醇—异辛烷混合燃料的滞燃期影响较大,当初始温度增加时,滞燃期大幅缩短;部分掺醇混合燃料(掺醇率低于25%)中甲醇含量对燃料滞燃期的影响因温度范围的不同而不同,在850 K以下甲醇比率增加使混合燃料滞燃期延长,在850 K以上甲醇比率增加使其滞燃期缩短。

The characteristic comparison of methanol ignition delay period between Curran＇s isooctane detailed chemical kinetic mechanism and Li＇s methanol chemical kinetic mechanism was researched. It was found that Curran＇s isooctane chemical kinetic mechanism could simulate the process of methanol spontaneous combustion more effectively. The ignition delay period of methanol-isooctane blended fuel was calculated and researched with Curran＇s mechanism under the condition of the initial temperature range from 600 K to 1 600 K, the pressure range from 1.0 MPa to 4.0 MPa and the equivalence ratio range from 0.3 to 1.5, and the influences of fuel characteristics and initial conditions on ignition delay period of blended fuel were analyzed for further. The results showed that the initial temperature had the important influence that the ignition delay period decreased with the increase of initial temperature. It was also indicated that the methanol content of blended fuel mixed with methanol （especially for the blended fuel that the methanol content was less than 25 percent） had different influences on the ignition delay period in different temperature ranges. When the initial temperature was less than 850 K, the increase of methanol content prolonged the ignition delay time. When the initial temperature was more than 850 K, the decrease of methanol content shortened the ignition delay time.