基于动态全增厚火焰模型对甲烷／空气非预混燃烧的大涡模拟

Large-Eddy Simulation of Methane/Air Non-Premixed Combustion Using Dynamically Full Thickened Flame Model

采用基于释热率构造火焰面探测函数的动态全增厚火焰模型,结合全可压缩大涡模拟方法,对甲烷/空气同轴射流燃烧器的非预混燃烧进行模拟。将此计算结果与动态增厚火焰模型、稳态层流小火焰模型的计算结果及实验值进行比较。结果表明,前两者能够准确捕捉到燃烧器进口前的抬升火焰。动态全增厚火焰模型预测的混合分数、燃烧产物和一氧化碳的分布与实验值非常吻合,且该模型可捕捉到燃烧的全部火焰面。

A newly proposed Dynamically Full Thickened Flame （DFTF） Model, which flame front sensor is based on heat release rate, is combined with fully compressible large-eddy simulation to study a Coaxial Methane/air Jet Combustor＇s non-premixed flame. The comparison with the dynamically thickened flame model results and the steady flamelet model results as will as experimental results show that in the region near the inlet, the front two models can exactly capture the lift-off flame. The predicted mixture fraction, reaction products concentration and carbon monoxide concentration by DFTF model were in good agreement with experiment data. The DFTF model can capture full flame front in eombustor.