乙烯燃烧化学动力学机理的简化与分析

为了获得高精度、小尺寸的乙烯简化机理,采用基于误差传播的直接关系图(DRGEP)法和反应路径分析(PFA)法对USC(University of Southern California)-Ⅱ机理在宽范围工况下进行简化,通过取交集方式得到了包含38个组分和243个反应的框架机理,采用灵敏性分析得到了包含30个组分和167个反应的框架机理,其最大点火延时误差为7.10%。在较宽的工况范围内对30个组分的框架机理进行了验证与机理分析,结果表明:此框架机理在点火延时,火焰传播速度,温度曲线,组分摩尔分数曲线,反应的灵敏性系数,反应路径和不确定性等燃烧特性参数与详细机理吻合较好。通过准稳态假设(QSSA)方法简化得到了更适用于工程应用的24个组分和20个总包反应的全局简化机理,并验证了其点火延时。 

Skeletal chemical kinetic model generation and analysis for combustion of ethylene

The detailed chemical kinetic mechanism for ethylene was systematically reduced and analyzed using USC(University of Southern California)-Ⅱ mechanism with directed relation graph with error propagation (DRGEP) and path flux analysis (PFA) methods under the wide range of conditions. A skeletal mechanism with 38 species and 243 reactions was achieved from intersection of the two resulting skeletal mechanisms in the first-stage reduction. A skeletal mechanism of ethylene with 30 species and 167 reactions was obtained using sensitivity analysis in the further reduction, and maximum auto-ignition error was 7.10% under the above simulation conditions. This 30 species mechanism showed that, the auto-ignition delay times, laminar flame speeds, temperature and species profiles, brute-force sensitivity coefficients, reaction paths and uncertainty analysis were in good agreement with those of the detailed mechanism. At last, a reduced mechanism including 24 species and 20 global reactions was obtained using the quasi steady state approximation (QSSA) method. This mechanism reproduced satisfactorily auto-ignition delay times, making it more suitably for combustion modeling of engines.