【摘要】 基于Open FOAM开发了小火焰生成流型模型,并针对ECN(enginecombustionnetwork)SprayH(正庚烷喷雾燃烧)进行了数值模拟,研究了该模型对喷雾燃烧数值模拟的适用性.结果表明,该模型能够很好地捕捉着火延迟等特征参数.同时对比了基于OH质量分数和温升两种火焰浮起长度定义,结果显示前者对取值更不敏感,且能与实验更好地吻合.此外,深入分析了着火位置和燃烧发展历程,结果表明,在氧体积分数8%和12%工况,着火点的当量比均在0.8左右.对于氧体积分数15%工况,反应进度变量集中生成的区域对应于温度峰值,燃烧最迅速区域的当量比略大于1.更多还原

【Abstract】 A flamelet generated manifold(FGM)model is developed in the framework of OpenFOAM.Welldocumented(engine combustion network ECN)n-heptane spray combustion known as Spray H is simulated to assess the applicability of FGM model in spray combustion modelling.The results show that the FGM model can precisely capture ignition delay.The comparison of lift-off length based on two different criteria,namely OH mass fraction and temperature rise,indicates that the OH-based definition is less sensitive to threshold value and is in better agreement with the experimental results.In addition,an in-depth analysis of ignition location and combustion process was conducted,showing that ignition happens with the equivalence ratio around 0.8 under both 8% and 12% oxygen concentration.The concentrated production of progress variable corresponds to the temperature peak,and the fastest combustion occurs in the slightly fuel rich zone,where the equivalence ratio is marginally greater than 1.更多还原