生物柴油替代物高温燃烧机理

High Temperature Combustion Mechanism of Biodiesel Surrogate

生物柴油替代物详细化学反应动力学机理(简称详细机理)复杂,难以运用于三维数值模拟,因此有必要对其进行简化。基于Herbinet等建立的癸酸甲酯详细机理(2878种组分、8555个反应),采用直接关系图法、耦合路径通量分析和敏感性分析方法,构建了一个包含118种组分、722个反应的生物柴油替代物高温骨架机理。结果表明:在温度为1100~1800 K、压力为0.1~5.0 MPa、燃空比为0.5~2.0条件下,点火延迟时间、反应体系温度、主要组分含量(摩尔分数)、熄火温度以及火焰传播速度等的高温骨架机理模拟结果与详细机理结果基本一致;高温骨架机理能较好地再现详细机理的反应特点和燃烧特性,验证了高温骨架机理的可靠性。对高温骨架机理的温度敏感性分析结果表明,高温条件下燃料高温裂解以及小分子之间的反应最为重要。

Detailed combustion mechanism of biodiesel surrogate is complex and it is difficult to be applied in three-dimensional numerical simulation.Thus it is necessary to simplify the detailed mechanism.Based on the detailed reaction mechanism of methyl decanoate established by Herbinet et al.(2878 components,8555 reactions),a high temperature skeletal mechanism of biodiesel surrogate containing 118 species,722 reactions was built with using direct relation graph,coupled path flux and sensitivity analysis.Under the conditions of temperature 1100-1800 K,pressure 0.1-5.0 MPa,and equivalence ratio 0.5-2.0,calculation results of ignition delay time,reaction temperature,main species mole fraction,extinction temperature and laminar flame speed are all in good agreement with those of the detailed mechanism.In addition,the skeletal mechanism can well reproduce both reaction and combustion characteristics of the detailed mechanism.This proves the reliability of the skeletal mechanism.Temperature sensitivity analysis of the skeletal mechanism shows that,under high temperature conditions,high temperature decomposition of the fuel and reactions among small molecules are the two most important factors.